Let robolectric_manifest be specified as output of another rule
Let robolectric_manifest be specified as output of another rule

Summary:
This lets the `robolectric_manifest` be set to the output of another
rule like an `export_file` etc. similar to how `android_manifest` allows
in the `skeleton` parameter.

Closes https://github.com/facebook/buck/pull/1282

Test Plan: CI + Uber

Reviewed By: dreiss

fbshipit-source-id: 7835cdb

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