pip installs are hanging for xqueue

We were hanging on this:

```
Obtaining pika from
git+https://github.com/pika/pika.git@a731347fc0#egg=pika (from -r
/edx/app/xqueue/xqueue/requirements.txt (line 14))
  git clone in /edx/app/xqueue/venvs/xqueue/src/pika exists with URL
git://github.com/pika/pika.git
  The plan is to install the git repository
https://github.com/pika/pika.git
What to do?  (s)witch, (i)gnore, (w)ipe, (b)ackup
```
Merge pull request #1549 from edx/jarv/exists-actions-w-for-xqueue

pip installs are hanging for xqueue