Check if repository is a mount and not just a directory
Check if repository is a mount and not just a directory

Summary: Renaming a repository fails when repositories are mount points.

Test Plan: Kicking off sandcastle tests

Reviewed By: dorserg, Coneko

fbshipit-source-id: e41446c

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