Remove unused methods

o glance/common/utils.py:
  def add_features_to_http_headers(features, headers):

  This method was removed in the following commit.

    commit 76c3620c7effb15be577450c276db1e394c2de3e
    Author: Brian Waldon <bcwaldon@gmail.com>
    Date:   Fri Sep 7 17:21:34 2012 -0700

        Drop Glance Client

  In this case, it has been used only in the following test program.

  - glance/tests/unit/common/test_utils.py

o glance/tests/functional/__init__.py:    def reload_server(self,

  This method was removed in the following commit.

    commit 866cb846f5310e1ad36181e64e7d59ba54d9fd40
    Author: John Bresnahan <jbresnah@redhat.com>
    Date:   Fri May 3 10:50:42 2013 -1000

        Remove glance-control from the test suite

The following methods are not used(w/o tests), however, it can not be
deleted, added the comment.

o glance/common/location_strategy/__init__.py:
  def verify_location_strategy(conf=None,
      strategies=_available_strategies):

Change-Id: I50e3fdb6e929337b946e3534c8e7dbff77ac7998
Merge "Remove unused methods"