repogetbranch: Also support detecting "master" branch
repogetbranch: Also support detecting "master" branch

Change-Id: I6c93bf4f0619c430d1da0193fa9d6ed2fc9c89ab
Signed-off-by: Adrian DC <01fb3892f39957945220431e7409156544d2f041@gmail.com>

AdrianDC/android_development_shell_tools,AdrianDC/android_development_shell_tools