Integrate OSprofiler and Glance

*) Add osprofiler wsgi middleware
This middleware is used for 2 things:
1) It checks that person who want to trace is trusted and knows
secret HMAC key.
2) It start tracing in case of proper trace headers
and add first wsgi trace point, with info about HTTP request

*) Add initialization of osprofiler at start of serivce
Set's olso.messaging notifer instance (to send notifications to
Ceilometer)

*) Add tracing support for sqlalchemy

*) Add profiler CONF group that has to options:
1) Enable or disable profiler
2) Enable or disable sqlalchemy tracing
(the reason why we put this in Conf options, is that usually
db requests create a lot of trace info)

*) Glance-registry wasn't setted properly to send notifications.

To test it you need 2 things:
1) Enable ceilometer in devstack:
http://paste.openstack.org/show/85724/
2) Initialize osprofiler and send out API request. You can use
one of follow approaches:
a. Run this script (pls provide proper credentials)
http://paste.openstack.org/show/85722/
b. Use the function https://review.openstack.org/#/c/111184/
added from glanceclient CLI directly.

DocImpact

Change-Id: I45a19f5eb5304c2b78a9e12cbc0744941a807304
Co-author: Zhi Yan Liu <zhiyanl@cn.ibm.com>#