Merge branch 'jg/status-config'

"git status" learned status.branch and status.short configuration
variables to use --branch and --short options by default (override
with --no-branch and --no-short options from the command line).

* jg/status-config:
  status/commit: make sure --porcelain is not affected by user-facing config
  commit: make it work with status.short
  status: introduce status.branch to enable --branch by default
  status: introduce status.short to enable --short by default

wt-status.c

@@ -127,6 +127,7 @@ void wt_status_prepare(struct wt_status *s)
 	s->change.strdup_strings = 1;
 	s->untracked.strdup_strings = 1;
 	s->ignored.strdup_strings = 1;
+	s->show_branch = -1;  /* unspecified */
 }
 
 static void wt_status_print_unmerged_header(struct wt_status *s)