Add Freezer modules and projects for Mitaka release

Added the following modules to global-requirements.txt
and upper-contraints.txt:

- apscheduler
Is the library actively maintained?
Yes, last version releaset 2015-12-10 as per
    - https://pypi.python.org/pypi/APScheduler/3.0.5

Is the library good code?
The library provides:
    Tests:
    - https://bitbucket.org/agronholm/apscheduler/src/a6545cf29831?at=master
    Extensive documentation:
    - http://apscheduler.readthedocs.org/en/3.0/
    Active bug tracking:
    - https://bitbucket.org/agronholm/apscheduler/issues?status-new&status-open

Is the library python 3 compatible?
    - It support ptyhon>=3.3

Is the library license compatible?
    - Library license is MIT, thus a compatible license

Is the library already packaged in the distros we target (Ubuntu latest / Fedora latest)?
    - Debian:
        - https://packages.debian.org/jessie/all/python-apscheduler/download
    - Fedora:
        - https://admin.fedoraproject.org/pkgdb/package/rpms/python-APScheduler/

Is the function of this library already covered by other libraries in global-requirements.txt
    - As far as we can see, there's not other scheduling related module available.

Change-Id: Iba93963f5e633f3711b26e7eed16a5b623e7683d
Depends-On: Iae75d00f6b3d18c55b32fd11b91836a1ce4ddd95

global-requirements.txt

@@ -3,6 +3,7 @@ alembic>=0.8.0  # MIT
 amqp>=1.4.0  # LGPL
 anyjson>=0.3.3  # BSD
 appdirs>=1.3.0  # MIT License
+apscheduler # MIT License
 argcomplete>=0.6.8  # Apache-2.0
 astroid<1.4.0  # LGPL # breaks pylint 1.4.4
 autobahn>=0.10.1  # MIT License

projects.txt

@@ -24,6 +24,9 @@ openstack/diskimage-builder
 openstack/django_openstack_auth
 openstack/dragonflow
 openstack/ekko
+openstack/freezer
+openstack/freezer-api
+openstack/freezer-web-ui
 openstack/futurist
 openstack/glance
 openstack/glance_store

upper-constraints.txt

@@ -62,6 +62,7 @@ amqp===1.4.9
 anyjson===0.3.3
 aodhclient===0.2.0
 appdirs===1.4.0
+apscheduler===3.0.5
 argcomplete===1.1.0
 astroid===1.3.8
 attrs===15.2.0