Do not return empty annotation processor params if annotation processor deps are present
Do not return empty annotation processor params if annotation processor deps are present

Summary:
Tools like [error-prone](https://github.com/google/error-prone) pickup custom error prone checks from the `-processorpath`. This change makes it so that annotation processor deps are always added to processor path if they exist regardless of the existence of annotation processors
Closes https://github.com/facebook/buck/pull/1213

Reviewed By: dreiss, jkeljo

fbshipit-source-id: 566bf7e

clonetwin26/buck,zhan-xiong/buck,rmaz/buck,robbertvanginkel/buck,marcinkwiatkowski/buck,brettwooldridge/buck,Addepar/buck,JoelMarcey/buck,grumpyjames/buck,clonetwin26/buck,zhan-xiong/buck,darkforestzero/buck,kageiit/buck,vschs007/buck,darkforestzero/buck,zhan-xiong/buck,dsyang/buck,JoelMarcey/buck,LegNeato/buck,vschs007/buck,robbertvanginkel/buck,SeleniumHQ/buck,clonetwin26/buck,shs96c/buck,SeleniumHQ/buck,robbertvanginkel/buck,shs96c/buck,Addepar/buck,brettwooldridge/buck,nguyentruongtho/buck,ilya-klyuchnikov/buck,LegNeato/buck,davido/buck,rmaz/buck,grumpyjames/buck,rmaz/buck,clonetwin26/buck,shs96c/buck,ilya-klyuchnikov/buck,marcinkwiatkowski/buck,JoelMarcey/buck,rmaz/buck,clonetwin26/buck,vschs007/buck,zhan-xiong/buck,facebook/buck,JoelMarcey/buck,shybovycha/buck,dsyang/buck,Addepar/buck,zpao/buck,marcinkwiatkowski/buck,clonetwin26/buck,rmaz/buck,brettwooldridge/buck,vschs007/buck,k21/buck,shybovycha/buck,kageiit/buck,marcinkwiatkowski/buck,robbertvanginkel/buck,grumpyjames/buck,grumpyjames/buck,brettwooldridge/buck,JoelMarcey/buck,marcinkwiatkowski/buck,shybovycha/buck,SeleniumHQ/buck,dsyang/buck,shs96c/buck,romanoid/buck,darkforestzero/buck,ilya-klyuchnikov/buck,k21/buck,JoelMarcey/buck,shybovycha/buck,brettwooldridge/buck,marcinkwiatkowski/buck,zpao/buck,SeleniumHQ/buck,SeleniumHQ/buck,JoelMarcey/buck,brettwooldridge/buck,k21/buck,k21/buck,robbertvanginkel/buck,JoelMarcey/buck,shs96c/buck,grumpyjames/buck,clonetwin26/buck,zhan-xiong/buck,robbertvanginkel/buck,rmaz/buck,dsyang/buck,robbertvanginkel/buck,rmaz/buck,rmaz/buck,Addepar/buck,ilya-klyuchnikov/buck,grumpyjames/buck,Addepar/buck,vschs007/buck,zpao/buck,nguyentruongtho/buck,grumpyjames/buck,rmaz/buck,grumpyjames/buck,LegNeato/buck,SeleniumHQ/buck,dsyang/buck,zhan-xiong/buck,dsyang/buck,marcinkwiatkowski/buck,nguyentruongtho/buck,robbertvanginkel/buck,shs96c/buck,davido/buck,romanoid/buck,rmaz/buck,brettwooldridge/buck,shybovycha/buck,romanoid/buck,shs96c/buck,romanoid/buck,JoelMarcey/buck,kageiit/buck,dsyang/buck,shs96c/buck,ilya-klyuchnikov/buck,k21/buck,zpao/buck,Addepar/buck,dsyang/buck,davido/buck,Addepar/buck,k21/buck,k21/buck,vschs007/buck,clonetwin26/buck,darkforestzero/buck,grumpyjames/buck,romanoid/buck,facebook/buck,marcinkwiatkowski/buck,ilya-klyuchnikov/buck,romanoid/buck,Addepar/buck,darkforestzero/buck,brettwooldridge/buck,zhan-xiong/buck,clonetwin26/buck,ilya-klyuchnikov/buck,zhan-xiong/buck,nguyentruongtho/buck,Addepar/buck,romanoid/buck,robbertvanginkel/buck,rmaz/buck,robbertvanginkel/buck,marcinkwiatkowski/buck,k21/buck,ilya-klyuchnikov/buck,JoelMarcey/buck,romanoid/buck,Addepar/buck,brettwooldridge/buck,shybovycha/buck,dsyang/buck,Addepar/buck,facebook/buck,vschs007/buck,JoelMarcey/buck,davido/buck,brettwooldridge/buck,davido/buck,LegNeato/buck,marcinkwiatkowski/buck,darkforestzero/buck,shybovycha/buck,shs96c/buck,dsyang/buck,LegNeato/buck,grumpyjames/buck,darkforestzero/buck,facebook/buck,davido/buck,LegNeato/buck,k21/buck,kageiit/buck,rmaz/buck,clonetwin26/buck,marcinkwiatkowski/buck,davido/buck,davido/buck,robbertvanginkel/buck,dsyang/buck,dsyang/buck,davido/buck,zpao/buck,SeleniumHQ/buck,LegNeato/buck,shybovycha/buck,k21/buck,ilya-klyuchnikov/buck,zhan-xiong/buck,JoelMarcey/buck,brettwooldridge/buck,LegNeato/buck,facebook/buck,marcinkwiatkowski/buck,clonetwin26/buck,darkforestzero/buck,romanoid/buck,brettwooldridge/buck,davido/buck,SeleniumHQ/buck,Addepar/buck,vschs007/buck,zhan-xiong/buck,shybovycha/buck,romanoid/buck,SeleniumHQ/buck,darkforestzero/buck,k21/buck,romanoid/buck,kageiit/buck,dsyang/buck,vschs007/buck,marcinkwiatkowski/buck,LegNeato/buck,romanoid/buck,shybovycha/buck,facebook/buck,darkforestzero/buck,davido/buck,robbertvanginkel/buck,LegNeato/buck,JoelMarcey/buck,grumpyjames/buck,brettwooldridge/buck,shybovycha/buck,facebook/buck,shs96c/buck,k21/buck,nguyentruongtho/buck,vschs007/buck,grumpyjames/buck,shs96c/buck,clonetwin26/buck,shs96c/buck,SeleniumHQ/buck,vschs007/buck,darkforestzero/buck,shybovycha/buck,robbertvanginkel/buck,clonetwin26/buck,darkforestzero/buck,SeleniumHQ/buck,zpao/buck,Addepar/buck,nguyentruongtho/buck,SeleniumHQ/buck,zpao/buck,davido/buck,shybovycha/buck,romanoid/buck,SeleniumHQ/buck,ilya-klyuchnikov/buck,rmaz/buck,LegNeato/buck,kageiit/buck,zhan-xiong/buck,LegNeato/buck,ilya-klyuchnikov/buck,zhan-xiong/buck,nguyentruongtho/buck,vschs007/buck,vschs007/buck,ilya-klyuchnikov/buck,ilya-klyuchnikov/buck,davido/buck,darkforestzero/buck,LegNeato/buck,shs96c/buck,k21/buck,zhan-xiong/buck,kageiit/buck