Protect against cases where the devserver can be slow to start up.

These can happen if the devserver is busy cleaning its cache
and the system is under heavy IO. There's really little reason to
have a small timeout so let's play it safe it bounce it up a lot.

BUG=chromium-os:34768
TEST=Ran cros_generate_test_payloads

Change-Id: I578f222ac63dc3ca8d65bee7dca0a504ce9e07f0
Reviewed-on: https://gerrit.chromium.org/gerrit/39514
Tested-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
Commit-Ready: Chris Sosa <sosa@chromium.org>
diff --git a/lib/dev_server_wrapper.py b/lib/dev_server_wrapper.py
index 03c9a76..595fd99 100644
--- a/lib/dev_server_wrapper.py
+++ b/lib/dev_server_wrapper.py
@@ -11,8 +11,9 @@
 
 import cros_build_lib as cros_lib
 
-# Wait up to 3 minutes for the dev server to start.
-DEV_SERVER_TIMEOUT = 180
+# Wait up to 15 minutes for the dev server to start. It can take a while to
+# start when generating payloads in parallel.
+DEV_SERVER_TIMEOUT = 900
 
 def GenerateUpdateId(target, src, key, for_vm):
   """Returns a simple representation id of target and src paths."""