Merge branch 'cl/p4-use-diff-tree'

Fixes a regression in 1.9.0 with an obviously correct single-liner.

* cl/p4-use-diff-tree:
  git-p4: format-patch to diff-tree change breaks binary patches

git-p4.py

@@ -1311,7 +1311,7 @@ class P4Submit(Command, P4UserMap):
             else:
                 die("unknown modifier %s for %s" % (modifier, path))
 
-        diffcmd = "git diff-tree -p \"%s\"" % (id)
+        diffcmd = "git diff-tree --full-index -p \"%s\"" % (id)
         patchcmd = diffcmd + " | git apply "
         tryPatchCmd = patchcmd + "--check -"
         applyPatchCmd = patchcmd + "--check --apply -"