Fix for license check job.

Somehow, having the '!' before a single command in a single line parses out the '!'.

Author: cmonr

.travis.yml

@@ -303,8 +303,10 @@ matrix:
         - NAME=licence_check
       script:
         - echo 'Checking that there is no GPL licence text in code'
-        - ! git grep -q --ignore-case "gnu general public";
-        - ! git grep -q --ignore-case "gnu library general public";
+        - |
+          ! git grep -q --ignore-case "gnu general public";
+        - |
+          ! git grep -q --ignore-case "gnu library general public";
 
     - env:
         - NAME=include_check