Add a user friendly symlink to the log dir of the last run command
Add a user friendly symlink to the log dir of the last run command

Summary: This is handy for the most common case when inspecting the logs of the command that was last run.

Test Plan: run a couple of buck build and buck target commands, verify symlinks are correct

Reviewed By: beefon

fbshipit-source-id: 854360c

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