Fix watchman integration when watchman fails to load
Fix watchman integration when watchman fails to load

Summary:
Previously, if watchman failed to load initially, it would pass the string
'None' into java, which was then interpretted as a file path and things broke.
Now we catch this issue and send a good-enough root (the buck project root)
down, which is what would have happened before the root/relativepath change
anyway.

Test Plan:
Ran

  watchman shutdown-server && ../buck/bin/buck kill && ../buck/bin/buckbuild 4a4

In two situations 1) normal watchman works case, 2) I deleted the watchman root
from the json response and ran it again (this would throw an exception before).

siddhartharay007/buck,janicduplessis/buck,artiya4u/buck,Dominator008/buck,vine/buck,LegNeato/buck,dsyang/buck,sdwilsh/buck,sdwilsh/buck,neonichu/buck,luiseduardohdbackup/buck,kageiit/buck,ilya-klyuchnikov/buck,dushmis/buck,brettwooldridge/buck,zhan-xiong/buck,Distrotech/buck,zhan-xiong/buck,brettwooldridge/buck,brettwooldridge/buck,vschs007/buck,pwz3n0/buck,rowillia/buck,raviagarwal7/buck,grumpyjames/buck,grumpyjames/buck,mnuessler/buck,zhan-xiong/buck,rhencke/buck,mogers/buck,robbertvanginkel/buck,mikekap/buck,bocon13/buck,clonetwin26/buck,ilya-klyuchnikov/buck,k21/buck,artiya4u/buck,LegNeato/buck,zpao/buck,Heart2009/buck,justinmuller/buck,sdwilsh/buck,stuhood/buck,tgummerer/buck,dsyang/buck,OkBuilds/buck,luiseduardohdbackup/buck,kageiit/buck,k21/buck,ilya-klyuchnikov/buck,shybovycha/buck,dushmis/buck,zhuxiaohao/buck,mikekap/buck,romanoid/buck,romanoid/buck,siddhartharay007/buck,shs96c/buck,stuhood/buck,sdwilsh/buck,janicduplessis/buck,Heart2009/buck,rowillia/buck,OkBuilds/buck,justinmuller/buck,pwz3n0/buck,zhuxiaohao/buck,brettwooldridge/buck,janicduplessis/buck,Dominator008/buck,1yvT0s/buck,zpao/buck,stuhood/buck,ilya-klyuchnikov/buck,shs96c/buck,illicitonion/buck,rmaz/buck,nguyentruongtho/buck,mnuessler/buck,pwz3n0/buck,Heart2009/buck,rhencke/buck,dsyang/buck,bocon13/buck,liuyang-li/buck,mogers/buck,Distrotech/buck,rhencke/buck,daedric/buck,darkforestzero/buck,1yvT0s/buck,vschs007/buck,grumpyjames/buck,illicitonion/buck,ilya-klyuchnikov/buck,mikekap/buck,stuhood/buck,rmaz/buck,Dominator008/buck,pwz3n0/buck,k21/buck,SeleniumHQ/buck,darkforestzero/buck,Dominator008/buck,daedric/buck,illicitonion/buck,k21/buck,robbertvanginkel/buck,rowillia/buck,davido/buck,brettwooldridge/buck,marcinkwiatkowski/buck,daedric/buck,clonetwin26/buck,marcinkwiatkowski/buck,shs96c/buck,Dominator008/buck,OkBuilds/buck,ilya-klyuchnikov/buck,zpao/buck,mogers/buck,zhan-xiong/buck,brettwooldridge/buck,artiya4u/buck,zhan-xiong/buck,raviagarwal7/buck,rmaz/buck,Learn-Android-app/buck,ilya-klyuchnikov/buck,clonetwin26/buck,pwz3n0/buck,Learn-Android-app/buck,stuhood/buck,rmaz/buck,tgummerer/buck,Addepar/buck,davido/buck,hgl888/buck,vine/buck,tgummerer/buck,brettwooldridge/buck,liuyang-li/buck,vine/buck,vine/buck,kageiit/buck,vschs007/buck,shybovycha/buck,neonichu/buck,davido/buck,dushmis/buck,LegNeato/buck,dsyang/buck,Learn-Android-app/buck,justinmuller/buck,artiya4u/buck,sdwilsh/buck,lukw00/buck,vine/buck,k21/buck,nguyentruongtho/buck,grumpyjames/buck,1yvT0s/buck,Distrotech/buck,SeleniumHQ/buck,daedric/buck,darkforestzero/buck,shs96c/buck,bocon13/buck,dushmis/buck,hgl888/buck,OkBuilds/buck,Heart2009/buck,janicduplessis/buck,daedric/buck,tgummerer/buck,luiseduardohdbackup/buck,hgl888/buck,mnuessler/buck,clonetwin26/buck,artiya4u/buck,janicduplessis/buck,k21/buck,vschs007/buck,neonichu/buck,vschs007/buck,marcinkwiatkowski/buck,OkBuilds/buck,romanoid/buck,rmaz/buck,LegNeato/buck,mogers/buck,bocon13/buck,JoelMarcey/buck,darkforestzero/buck,artiya4u/buck,mogers/buck,brettwooldridge/buck,romanoid/buck,Distrotech/buck,siddhartharay007/buck,shybovycha/buck,romanoid/buck,OkBuilds/buck,facebook/buck,rmaz/buck,Addepar/buck,raviagarwal7/buck,Heart2009/buck,rhencke/buck,rowillia/buck,artiya4u/buck,mogers/buck,OkBuilds/buck,Learn-Android-app/buck,rhencke/buck,liuyang-li/buck,daedric/buck,liuyang-li/buck,OkBuilds/buck,dsyang/buck,Addepar/buck,k21/buck,clonetwin26/buck,rowillia/buck,nguyentruongtho/buck,Distrotech/buck,grumpyjames/buck,shybovycha/buck,janicduplessis/buck,hgl888/buck,kageiit/buck,raviagarwal7/buck,k21/buck,Learn-Android-app/buck,Learn-Android-app/buck,artiya4u/buck,davido/buck,k21/buck,siddhartharay007/buck,romanoid/buck,lukw00/buck,zhan-xiong/buck,lukw00/buck,OkBuilds/buck,zhan-xiong/buck,neonichu/buck,grumpyjames/buck,janicduplessis/buck,OkBuilds/buck,mikekap/buck,Distrotech/buck,vine/buck,mnuessler/buck,zpao/buck,robbertvanginkel/buck,shybovycha/buck,marcinkwiatkowski/buck,darkforestzero/buck,kageiit/buck,liuyang-li/buck,SeleniumHQ/buck,mikekap/buck,vschs007/buck,JoelMarcey/buck,JoelMarcey/buck,siddhartharay007/buck,Heart2009/buck,illicitonion/buck,zhuxiaohao/buck,dsyang/buck,hgl888/buck,SeleniumHQ/buck,sdwilsh/buck,illicitonion/buck,facebook/buck,Addepar/buck,luiseduardohdbackup/buck,marcinkwiatkowski/buck,neonichu/buck,pwz3n0/buck,dushmis/buck,dsyang/buck,Addepar/buck,marcinkwiatkowski/buck,rmaz/buck,dsyang/buck,pwz3n0/buck,davido/buck,Addepar/buck,Distrotech/buck,Addepar/buck,facebook/buck,SeleniumHQ/buck,Addepar/buck,rhencke/buck,SeleniumHQ/buck,clonetwin26/buck,raviagarwal7/buck,bocon13/buck,davido/buck,raviagarwal7/buck,illicitonion/buck,mikekap/buck,liuyang-li/buck,shybovycha/buck,shybovycha/buck,Learn-Android-app/buck,zhan-xiong/buck,justinmuller/buck,janicduplessis/buck,zhuxiaohao/buck,dsyang/buck,dushmis/buck,rowillia/buck,vschs007/buck,robbertvanginkel/buck,davido/buck,darkforestzero/buck,zhuxiaohao/buck,vine/buck,luiseduardohdbackup/buck,SeleniumHQ/buck,lukw00/buck,rmaz/buck,artiya4u/buck,bocon13/buck,lukw00/buck,stuhood/buck,LegNeato/buck,lukw00/buck,rmaz/buck,Learn-Android-app/buck,zhan-xiong/buck,vine/buck,facebook/buck,Addepar/buck,LegNeato/buck,zhan-xiong/buck,1yvT0s/buck,davido/buck,rmaz/buck,darkforestzero/buck,justinmuller/buck,JoelMarcey/buck,robbertvanginkel/buck,nguyentruongtho/buck,stuhood/buck,LegNeato/buck,robbertvanginkel/buck,romanoid/buck,Distrotech/buck,ilya-klyuchnikov/buck,vine/buck,mikekap/buck,JoelMarcey/buck,tgummerer/buck,Learn-Android-app/buck,hgl888/buck,shs96c/buck,liuyang-li/buck,raviagarwal7/buck,Dominator008/buck,dushmis/buck,rmaz/buck,romanoid/buck,bocon13/buck,luiseduardohdbackup/buck,clonetwin26/buck,romanoid/buck,liuyang-li/buck,mogers/buck,Learn-Android-app/buck,zhan-xiong/buck,sdwilsh/buck,mogers/buck,mnuessler/buck,justinmuller/buck,clonetwin26/buck,rowillia/buck,OkBuilds/buck,OkBuilds/buck,stuhood/buck,illicitonion/buck,davido/buck,vine/buck,illicitonion/buck,k21/buck,vschs007/buck,neonichu/buck,bocon13/buck,lukw00/buck,janicduplessis/buck,bocon13/buck,ilya-klyuchnikov/buck,raviagarwal7/buck,clonetwin26/buck,LegNeato/buck,vine/buck,clonetwin26/buck,daedric/buck,Addepar/buck,rowillia/buck,JoelMarcey/buck,Dominator008/buck,pwz3n0/buck,tgummerer/buck,justinmuller/buck,justinmuller/buck,romanoid/buck,davido/buck,raviagarwal7/buck,brettwooldridge/buck,LegNeato/buck,illicitonion/buck,hgl888/buck,grumpyjames/buck,shybovycha/buck,zpao/buck,shs96c/buck,JoelMarcey/buck,daedric/buck,raviagarwal7/buck,facebook/buck,raviagarwal7/buck,shybovycha/buck,pwz3n0/buck,darkforestzero/buck,Distrotech/buck,shs96c/buck,marcinkwiatkowski/buck,liuyang-li/buck,brettwooldridge/buck,lukw00/buck,SeleniumHQ/buck,SeleniumHQ/buck,stuhood/buck,marcinkwiatkowski/buck,vschs007/buck,Addepar/buck,romanoid/buck,grumpyjames/buck,neonichu/buck,siddhartharay007/buck,liuyang-li/buck,tgummerer/buck,rhencke/buck,shs96c/buck,marcinkwiatkowski/buck,zpao/buck,bocon13/buck,dsyang/buck,1yvT0s/buck,illicitonion/buck,1yvT0s/buck,vschs007/buck,k21/buck,sdwilsh/buck,clonetwin26/buck,rmaz/buck,marcinkwiatkowski/buck,kageiit/buck,sdwilsh/buck,dsyang/buck,OkBuilds/buck,facebook/buck,bocon13/buck,clonetwin26/buck,darkforestzero/buck,ilya-klyuchnikov/buck,luiseduardohdbackup/buck,vschs007/buck,vschs007/buck,nguyentruongtho/buck,zhan-xiong/buck,sdwilsh/buck,Addepar/buck,neonichu/buck,tgummerer/buck,janicduplessis/buck,shs96c/buck,mnuessler/buck,rowillia/buck,justinmuller/buck,1yvT0s/buck,sdwilsh/buck,Distrotech/buck,Dominator008/buck,sdwilsh/buck,LegNeato/buck,mikekap/buck,kageiit/buck,mnuessler/buck,zhuxiaohao/buck,daedric/buck,Dominator008/buck,mikekap/buck,mnuessler/buck,shs96c/buck,Dominator008/buck,justinmuller/buck,vschs007/buck,darkforestzero/buck,artiya4u/buck,dushmis/buck,LegNeato/buck,ilya-klyuchnikov/buck,grumpyjames/buck,dushmis/buck,davido/buck,illicitonion/buck,luiseduardohdbackup/buck,tgummerer/buck,rhencke/buck,daedric/buck,shybovycha/buck,janicduplessis/buck,illicitonion/buck,lukw00/buck,SeleniumHQ/buck,liuyang-li/buck,stuhood/buck,darkforestzero/buck,robbertvanginkel/buck,shybovycha/buck,grumpyjames/buck,siddhartharay007/buck,rowillia/buck,davido/buck,dsyang/buck,siddhartharay007/buck,mikekap/buck,mnuessler/buck,JoelMarcey/buck,rhencke/buck,romanoid/buck,1yvT0s/buck,marcinkwiatkowski/buck,clonetwin26/buck,janicduplessis/buck,LegNeato/buck,mikekap/buck,stuhood/buck,pwz3n0/buck,JoelMarcey/buck,illicitonion/buck,darkforestzero/buck,tgummerer/buck,daedric/buck,marcinkwiatkowski/buck,justinmuller/buck,Heart2009/buck,shs96c/buck,luiseduardohdbackup/buck,nguyentruongtho/buck,rowillia/buck,rhencke/buck,daedric/buck,brettwooldridge/buck,robbertvanginkel/buck,romanoid/buck,rmaz/buck,grumpyjames/buck,ilya-klyuchnikov/buck,Learn-Android-app/buck,SeleniumHQ/buck,Heart2009/buck,shs96c/buck,zhan-xiong/buck,raviagarwal7/buck,Addepar/buck,mogers/buck,JoelMarcey/buck,lukw00/buck,bocon13/buck,hgl888/buck,brettwooldridge/buck,daedric/buck,hgl888/buck,robbertvanginkel/buck,k21/buck,JoelMarcey/buck,zpao/buck,Dominator008/buck,shs96c/buck,pwz3n0/buck,brettwooldridge/buck,Distrotech/buck,JoelMarcey/buck,zhuxiaohao/buck,robbertvanginkel/buck,Dominator008/buck,robbertvanginkel/buck,1yvT0s/buck,justinmuller/buck,grumpyjames/buck,ilya-klyuchnikov/buck,lukw00/buck,rhencke/buck,robbertvanginkel/buck,marcinkwiatkowski/buck,facebook/buck,dushmis/buck,siddhartharay007/buck,JoelMarcey/buck,shybovycha/buck,SeleniumHQ/buck,zhuxiaohao/buck,robbertvanginkel/buck,mogers/buck,shybovycha/buck,sdwilsh/buck,justinmuller/buck,tgummerer/buck,nguyentruongtho/buck,rowillia/buck,neonichu/buck,zhuxiaohao/buck,artiya4u/buck,SeleniumHQ/buck,mogers/buck,mikekap/buck,raviagarwal7/buck,k21/buck,LegNeato/buck,davido/buck,dsyang/buck,Heart2009/buck,darkforestzero/buck