Only get the expensive branch mapping from the p4 server when not

syncing with the help of an origin remote (which we instead then use
to get new branches from).

git-p4

@@ -907,10 +907,6 @@ class P4Sync(Command):
             return p [p.strip().rfind("/") + 1:]
 
     def getBranchMapping(self):
-
-        ## FIXME - what's a P4 projectName ?
-        self.projectName = self.guessProjectName()
-
         for info in p4CmdList("branches"):
             details = p4Cmd("branch -o %s" % info["branch"])
             viewIdx = 0
@@ -1141,7 +1137,11 @@ class P4Sync(Command):
             self.getLabels();
 
         if self.detectBranches:
-            self.getBranchMapping();
+            ## FIXME - what's a P4 projectName ?
+            self.projectName = self.guessProjectName()
+
+            if not self.hasOrigin:
+                self.getBranchMapping();
             if self.verbose:
                 print "p4-git branches: %s" % self.p4BranchesInGit
                 print "initial parents: %s" % self.initialParents