Fix misspellings in devstack

Fix misspellings detected by:
 * pip install misspellings
 * git ls-files | grep -v locale | misspellings -f -

Change-Id: I19726438d15cd27b813504aac530e7e53c4def12
Closes-Bug: #1257295
Merge "Fix misspellings in devstack"
Merge commit 'refs/changes/71/70571/2' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch
Merge commit 'refs/changes/99/70999/4' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch