Updates .gitignore
Updates .gitignore

To ignore swap files from getting into repository
currently the implemented ignore is *.swp
however vim adds more swap files if these files exists,
so improving this with *.sw?

Change-Id: I48846345de6838735d2d2e46328698f6a526f397
Closes-Bug: #1255876

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