user defined headers added to swift post queries
user defined headers added to swift post queries

This commit fixes a problem where headers passed through the option
--header were not taken into account when doing "post" queries.

Change-Id: Ia34808c53a1816d9956a98e0803d8c4d20d2ad44
Closes-Bug: #1226256

sohonetlabs/python-swiftclient,iostackproject/IO-Bandwidth-Differentiation-Client,ironsmile/python-swiftclient,openstack/python-swiftclient,krnflake/python-hubicclient,JioCloud/python-swiftclient,JioCloud/python-swiftclient,VyacheslavHashov/python-swiftclient,sohonetlabs/python-swiftclient,pratikmallya/python-swiftclient,jeseem/python-swiftclient,openstack/python-swiftclient,pratikmallya/python-swiftclient,varunarya10/python-swiftclient,varunarya10/python-swiftclient,zackmdavis/python-swiftclient,zackmdavis/python-swiftclient,ironsmile/python-swiftclient,iostackproject/IO-Bandwidth-Differentiation-Client,jeseem/python-swiftclient,VyacheslavHashov/python-swiftclient