Use tester.py's built-in coverage and coverage.py's built-in cleanup

.travis.yml

@@ -30,7 +30,7 @@ script:
   - python setup.py clean
   - python setup.py build_ext --inplace
   - coverage run --append --include=PIL/* selftest.py
-  - coverage run --append --include=PIL/* Tests/run.py
+  - python Tests/run.py --coverage
 
 after_success:
   - coverage report

Tests/tester.py

@@ -285,13 +285,6 @@ def _setup():
             except OSError:
                 pass
 
-        if "--coverage" in sys.argv:
-            import coverage
-            coverage.stop()
-            # The coverage module messes up when used from inside an
-            # atexit handler.  Do an explicit save to make sure that
-            # we actually flush the coverage cache.
-            coverage.the_coverage.save()
     import atexit, sys
     atexit.register(report)
     if "--coverage" in sys.argv: