.gitignore: add an entry for repopickles

Signed-off-by: David Aguilar <davvid@gmail.com>
diff --git a/.gitignore b/.gitignore
index 0d20b64..cef6b78 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 *.pyc
+.repopickle_*