split out lint to a separate Travis job

In order to speed our Travis CI gating even further, the lint step has
been split to a separate job that can be run in parallel with the test
runs. The test runs are in turn launched in developer mode to speed them
up.

Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>
Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>

.travis.yml

@@ -5,10 +5,15 @@ services:
 env:
     global:
         - TEST_RUNNER_IMAGE="martbab/freeipa-fedora-test-runner:master-latest"
+          TEST_RUNNER_CONFIG=".test_runner_config.yaml"
+          PEP8_ERROR_LOG="pep8_errors.log"
+          CI_RESULTS_LOG="ci_results_${TRAVIS_BRANCH}.log"
     matrix:
-        - TESTS_TO_RUN="test_xmlrpc/test_[a-k]*.py"
-        - >
-            TESTS_TO_RUN="test_cmdline
+        - TASK_TO_RUN="lint"
+        - TASK_TO_RUN="run-tests"
+          TESTS_TO_RUN="test_xmlrpc/test_[a-k]*.py"
+        - TASK_TO_RUN="run-tests"
+          TESTS_TO_RUN="test_cmdline
             test_install
             test_ipalib
             test_ipapython
@@ -24,5 +29,5 @@ before_install:
 script:
     - travis_wait 50 ./.travis_run_task.sh
 after_failure:
-    - echo "Test runner output:"; tail -n 5000 ci_results_${TRAVIS_BRANCH}.log
-    - echo "PEP-8 errors:"; cat pep8_errors.log
+    - echo "Test runner output:"; tail -n 5000 $CI_RESULTS_LOG
+    - echo "PEP-8 errors:"; cat $PEP8_ERROR_LOG