Bug 1580354 - Handle spaces in bookmark names. r=zalun

Summary:
Only split once when reading output from hg bookmark to prevent
an error when a user-created bookmark contains a space character
in the name.

Reviewers: zalun

Reviewed By: zalun

Bug #: 1580354

Differential Revision: https://phabricator.services.mozilla.com/D45469

moz-phab

@@ -1749,7 +1749,7 @@ class Mercurial(Repository):
         # be deleted in cleanup(). Mercurial will automatically move the
         # bookmark to the successors as we update commits.
         for active, bookmark in [
-            l.split(" ")
+            l.split(" ", 1)
             for l in self.hg_out(["bookmark", "-T", "{active} {bookmark}\n"])
         ]:
             if active == "True":