tests: Travis conditional only run frontend tests if it's not a fork. (#4097)

.travis.yml

@@ -25,8 +25,10 @@ env:
 
 jobs:
   include:
-    - if: repo = ether/etherpad-lite
-    - name: "Test the Frontend"
+    # we can only frontend tests from the ether/ organization and not from forks.
+    # To request tests to be run ask a maintainer to fork your repo to ether/
+    - if: fork = false
+      name: "Test the Frontend"
       install:
         - "bin/installDeps.sh"
         - "export GIT_HASH=$(git rev-parse --verify --short HEAD)"