Add config to RESTRICTED_PATHS

We want to add the 'config' directory to the array of RESTRICTED_PATHS
in order to prevent accidental modifications to config files.

Change-Id: I1b1d0ef6e840219e5d8285a33e342fac6cd28b05
Reviewed-on: https://gerrit.causes.com/27592
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Kim Douglas Clarence Mason <kim.mason@causes.com>