devserver: Deprecate the --no_patch_kernel option.

It doesn't do anything any more, and it's not being used by any callers.

CQ-DEPEND=CL:216577
BUG=chromium:403031
TEST=Ran a butterfly-paladin trujob with --hwtest.

Change-Id: Ife2c452b98d0e11a22ad4416b15defb842710c24
Reviewed-on: https://chromium-review.googlesource.com/216611
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
diff --git a/devserver.py b/devserver.py
index 27cceeb..2ac4b9f 100755
--- a/devserver.py
+++ b/devserver.py
@@ -1057,11 +1057,6 @@
                    metavar='FILE',
                    help='Generate and serve an update using this image to any '
                    'device that requests an update.')
-  group.add_option('--no_patch_kernel',
-                   dest='patch_kernel', action='store_false', default=True,
-                   help='When generating an update payload, do not patch the '
-                   'kernel with kernel verification blob from the stateful '
-                   'partition.')
   group.add_option('--payload',
                    metavar='PATH',
                    help='use the update payload from specified directory '