Travis: don't run FIS integration tests on forks (#4580)

Author: maksymmalyhin

.travis.yml

@@ -652,7 +652,7 @@ jobs:
       env:
         - PROJECT=Installations PLATFORM=iOS METHOD=pod-lib-lint
         - FIS_ALLOWS_INCOMPATIBLE_IID_VERSION=1
-        - FIS_INTEGRATION_TESTS_REQUIRED=1
+        - FIS_INTEGRATION_TESTS_REQUIRED=$(if [[ "$TRAVIS_PULL_REQUEST" == "false" || "$TRAVIS_PULL_REQUEST_SLUG" == "$TRAVIS_REPO_SLUG" ]]; then echo "1"; else echo "0"; fi)
         - QUICKSTART=installations
       before_install:
         - ./scripts/if_changed.sh ./scripts/install_prereqs.sh
@@ -666,7 +666,7 @@ jobs:
       env:
         - PROJECT=Installations PLATFORM=macOS METHOD=pod-lib-lint
         - FIS_ALLOWS_INCOMPATIBLE_IID_VERSION=1
-        - FIS_INTEGRATION_TESTS_REQUIRED=1
+        - FIS_INTEGRATION_TESTS_REQUIRED=$(if [[ "$TRAVIS_PULL_REQUEST" == "false" || "$TRAVIS_PULL_REQUEST_SLUG" == "$TRAVIS_REPO_SLUG" ]]; then echo "1"; else echo "0"; fi)
       before_install:
         - ./scripts/if_changed.sh ./scripts/install_prereqs.sh
       script:
@@ -678,7 +678,7 @@ jobs:
       env:
         - PROJECT=Installations PLATFORM=tvOS METHOD=pod-lib-lint
         - FIS_ALLOWS_INCOMPATIBLE_IID_VERSION=1
-        - FIS_INTEGRATION_TESTS_REQUIRED=1
+        - FIS_INTEGRATION_TESTS_REQUIRED=$(if [[ "$TRAVIS_PULL_REQUEST" == "false" || "$TRAVIS_PULL_REQUEST_SLUG" == "$TRAVIS_REPO_SLUG" ]]; then echo "1"; else echo "0"; fi)
       before_install:
         - ./scripts/if_changed.sh ./scripts/install_prereqs.sh
       script: