LibStorageMgmt version 1.6.1 release

LibStorageMgmt version 1.6.1 released. Changes since 1.6.0: * Add support of RHEL/Centos 6 back. * Fix regression on SMI-S plugin. sha1sum: 605151517e6b21e597afedc690924e3a4c205313 libstoragemgmt-1.6.1.tar.gz https://github.com/libstorage/libstoragemgmt/releases/download/1.6.1/libs... -- Gris Ge