Fix Show Rights for HLS content

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

proprietary/drmwvmplugin/include/WVMDrmPlugin.h

@@ -131,6 +131,7 @@ private:
 
     static Vector<Listener> *sNativeListeners;
     static Vector<Listener> *sJavaAPIListeners;
+    static const char *sFileExtensions[];
 
     WVDRMPluginAPI *mDrmPluginImpl;
 };
@@ -138,4 +139,3 @@ private:
 };
 
 #endif /* __WVMDRMPLUGIN__ */
-