In WVMDrmPlugin.cpp, the supported suffixes was only .wvm. I changed this to
include .m3u8, .vob, .smil, and the empty extension. This allows the
WVMDrmPlugin to register itself as handling these files. If the plugin is not
registered, the "show rights" feature will not query the plugin.
related-to-bug: 6507440
Change-Id: Ib655760e46cfa4125d21beb9ff77e38b444ddc5a