TBR devtools/v23: changing the signup proxy logic so that it tries to push to the remote repository only if there are changes to be pushed
TBR devtools/v23: changing the signup proxy logic so that it tries to
push to the remote repository only if there are changes to be pushed

Also, the push command is fixed from "git push origin master" to "git
push origin update:master".

Change-Id: I1584f6b28e9638c84ed19ebfa6167d3e74239f3b

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools