Ensure that the ProjectFilesystem always usses an absolute path
Ensure that the ProjectFilesystem always usses an absolute path

Summary:
The `projectRoot` field was being shadowed by the `projectRoot`
constructor arg.

Test Plan: buck test --all

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