Don't exclude structure.sql from TrailingWhitespace by default

This shouldn't be something Overcommit specifies by default.

Change-Id: Ic5de6ac2845da4c34c3062a3a6bcd9eaf6580b9d
Reviewed-on: http://gerrit.causes.com/47230
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>

Author: sds

config/default.yml

@@ -322,8 +322,6 @@ PreCommit:
     description: 'Checking for trailing whitespace'
     required_executable: 'grep'
     flags: ['-IHn', '\s$']
-    exclude:
-      - '**/db/structure.sql'
 
   TravisLint:
     description: 'Checking Travis CI configuration'