Revert "circle: Ensure correct 0.1.0 tag is used"

Now that version is greater than 0.1.0, there is no need to keep this
workaround.

This reverts commit 0b124e2.

circle.yml

@@ -13,12 +13,6 @@ dependencies:
     - ci_addons docker load-pull-save dockcross/manylinux-x64
     - ci_addons docker load-pull-save dockcross/manylinux-x86
 
-checkout:
-  post:
-    # See https://discuss.circleci.com/t/clearing-the-source-cache/2771
-    - git tag -d 0.1.0 || true
-    - git fetch origin tag 0.1.0 || true
-
 test:
   override:
      - circleci-matrix: