Open 1.1.x development

The 1.1.x series will be for grizzly bugfix releases.

Change-Id: I041046bb97bf4072f598c91b8a127f4e6bba9f19
Set default branch in .gitreview to stable/grizzly

This allows people to run git-review without any arguments.

Change-Id: Id901d5b948e0419b944e9c7bc12152dc12226b87