Miscellaneous bug fixes for ansible-test.

- Overhauled coverage injector to fix issues with non-local tests.
- Updated integration tests to work with the new coverage injector.
- Fix concurrency issue by using random temp files for delegation.
- Fix handling of coverage files from root user.
- Fix handling of coverage files without arcs.
- Make sure temp copy of injector is world readable and executable.

test/runner/test.py

@@ -168,6 +168,10 @@ def parse_args():
                       action='store_true',
                       help='analyze code coverage when running tests')
 
+    test.add_argument('--coverage-label',
+                      default='',
+                      help='label to include in coverage output file names')
+
     test.add_argument('--metadata',
                       help=argparse.SUPPRESS)