stagefright-plugins: Remove voodoo from sniff logic
stagefright-plugins: Remove voodoo from sniff logic

 * We always run last, so if our confidence is high then add the
   necessary metadata.
 * Remove magic numbers.

Change-Id: I34ccffff7836495055610346dc8b99e36d855d5b

DirtyUnicorns/android_external_stagefright-plugins,AOSP-CAF/platform_external_stagefright-plugins,AOSPB/external_stagefright-plugins,SlimRoms/android_external_stagefright-plugins,SlimRoms/android_external_stagefright-plugins,PAC-ROM/android_external_stagefright-plugins,VRToxin/android_external_stagefright-plugins,AOSPB/external_stagefright-plugins,BrokenROM/external_stagefright-plugins,PAC-ROM/android_external_stagefright-plugins,TeamExodus/external_stagefright-plugins,Evervolv/android_external_stagefright-plugins,AOSP-CAF/platform_external_stagefright-plugins,Evervolv/android_external_stagefright-plugins,BrokenROM/external_stagefright-plugins,DirtyUnicorns/android_external_stagefright-plugins,TeamExodus/external_stagefright-plugins,VRToxin/android_external_stagefright-plugins