Bump alembic to 0.6.4 for Neutron

Recently merged neutron healing migration
(https://review.openstack.org/#/c/96438/)
needs alembic >= 0.6.4 for mysql.

The relevant fix in alembic:
    https://bitbucket.org/zzzeek/alembic/commits/b29780719904

Change-Id: If67241592ba82aed3b41b4acec17bd8d604a3c4b
Partial-Bug: #1342507
Update django_openstack_auth to 1.1.6

When keystone added pkiz it broke horizon, this version
is required for horizon to continue to work.

Change-Id: I2582d41235783ea160a43f8888035961d6cacd66
Bump pecan to >=0.5.0

This version has an improved test fixture required by
ironic-python-agent.

Change-Id: Ie1c246d12dad08ada1f99399713d43534d8d0148
Bump up the zake requirement to 0.0.26

Zake was released with a new version with bug fixes
and a addition of the emulation of one more of the
kazoo methods (transaction check support).

This change helps make it possible to test the fix
for bug 1343029 without requiring a full zookeeper
setup to test.

The zake *noteable* changes (for those interested):

- Add travis 3.4 builds
- Add more concurrent transaction tests
- Add much more robust transaction support
- Add basic check transaction support + tests
- Create all parent paths and child paths in the same lock context
- Address concurrent client variable modification
- Move znode making function to storage
- Add link to kazoo readthedocs
- Add test + fix for empty custom versions being provided
- Fix custom version in 'stat' response
- Ensure all paths are normalized before storage interaction

Change-Id: I376bddc78242f2fd559eb80856587c2c4d64b875
Merge "Bump up the zake requirement to 0.0.26"
Merge "Bump pecan to >=0.5.0"
Merge "Update django_openstack_auth to 1.1.6"
Merge "Bump alembic to 0.6.4 for Neutron"