diffmanifests: honour --pretty-format when printing --raw

Enable using --pretty-format to build a custom subject line
even when using the --raw option.

Change-Id: I0c1e682d984e56698fe65939aa6de12a653cd0f1
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/258565
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Connor Newton <connor@ifthenelse.io>

subcmds/diffmanifests.py

@@ -79,7 +79,7 @@ synced and their revisions won't be found.
                  metavar='<FORMAT>',
                  help='print the log using a custom git pretty format string')
 
-  def _printRawDiff(self, diff):
+  def _printRawDiff(self, diff, pretty_format=None):
     for project in diff['added']:
       self.printText("A %s %s" % (project.relpath, project.revisionExpr))
       self.out.nl()
@@ -92,7 +92,7 @@ synced and their revisions won't be found.
       self.printText("C %s %s %s" % (project.relpath, project.revisionExpr,
                                      otherProject.revisionExpr))
       self.out.nl()
-      self._printLogs(project, otherProject, raw=True, color=False)
+      self._printLogs(project, otherProject, raw=True, color=False, pretty_format=pretty_format)
 
     for project, otherProject in diff['unreachable']:
       self.printText("U %s %s %s" % (project.relpath, project.revisionExpr,
@@ -203,6 +203,6 @@ synced and their revisions won't be found.
 
     diff = manifest1.projectsDiff(manifest2)
     if opt.raw:
-      self._printRawDiff(diff)
+      self._printRawDiff(diff, pretty_format=opt.pretty_format)
     else:
       self._printDiff(diff, color=opt.color, pretty_format=opt.pretty_format)