Set defaultbranch in .gitreview to stable/grizzly
Set defaultbranch in .gitreview to stable/grizzly

This allows people run git-review without any arguments.

Change-Id: I7adde6608451268e8247944c297576a70280bf16

yrobla/nova,Triv90/Nova,Triv90/Nova,yrobla/nova,Triv90/Nova,yrobla/nova