Ignore extra coverge files

These files are created because we run acceptance tests in a subprocess.
They have the process id in their name, so they wont be removed by the
normal coverage cleanup on each run.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

.gitignore

@@ -1,6 +1,6 @@
 *.egg-info
 *.pyc
-/.coverage
+.coverage*
 /.tox
 /build
 /coverage-html

script/clean

@@ -2,5 +2,6 @@
 set -e
 
 find . -type f -name '*.pyc' -delete
+find . -name .coverage.* -delete
 find -name __pycache__ -delete
 rm -rf docs/_site build dist docker-compose.egg-info