Increase default sighup_timeout

It seems at times it takes more time than the current default
for the child processes to exit normally. Increasing it to
120 seconds.

Change-Id: Ic54d2d7edc97cbe07ed4a4445cb865bd1b157f9d
Closes-Bug: #1607177
diff --git a/common/config.py b/common/config.py
index b3615d2..3983792 100644
--- a/common/config.py
+++ b/common/config.py
@@ -133,7 +133,7 @@
                help="Timeout in seconds to wait for connectivity to "
                     "server."),
     cfg.IntOpt('sighup_timeout',
-               default=30,
+               default=120,
                help="Timeout in seconds to wait for adding or removing child"
                     "process after receiving of sighup signal"),
     cfg.IntOpt('sighup_config_edit_retries',