project: simplify GetRemote a bit

We almost always use self.remote.name when calling self.GetRemote,
so make that the default to simplify the code a bit.

Change-Id: Ifdf6e1370d6b8963b44e6d384b0fac8fa5c4f2ba
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/343184
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: LaMont Jones <lamontjones@google.com>

subcmds/version.py

@@ -33,7 +33,7 @@ class Version(Command, MirrorSafeCommand):
 
   def Execute(self, opt, args):
     rp = self.manifest.repoProject
-    rem = rp.GetRemote(rp.remote.name)
+    rem = rp.GetRemote()
     branch = rp.GetBranch('default')
 
     # These might not be the same.  Report them both.