python env: print more details when python --version fails
python env: print more details when python --version fails

Summary:
Previously, we'd just print a stock error message.  This diff includes
the message from the exception.  Also, avoid java's string tokenizer
when invoking the version command, since this won't handle spaces in
arguments correctly.

Test Plan: buck test --all

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