Merge branch 'ks/branch-set-upstream'

"branch --set-upstream" that has been deprecated in Git 1.8 has
finally been retired.

* ks/branch-set-upstream:
  branch: quote branch/ref names to improve readability
  builtin/branch: stop supporting the "--set-upstream" option
  t3200: cleanup cruft of a test

Documentation/git-branch.txt

@@ -195,10 +195,8 @@ start-point is either a local or remote-tracking branch.
 	branch.autoSetupMerge configuration variable is true.
 
 --set-upstream::
-	If specified branch does not exist yet or if `--force` has been
-	given, acts exactly like `--track`. Otherwise sets up configuration
-	like `--track` would when creating the branch, except that where
-	branch points to is not changed.
+	As this option had confusing syntax, it is no longer supported.
+	Please use `--track` or `--set-upstream-to` instead.
 
 -u <upstream>::
 --set-upstream-to=<upstream>::