Bug 1061219: Fix string conversion for A2DP connection states, r=shuang

The C++ compiler for Flatfish lacks support for initialized arrays of
C-string pointers. This patch fixes the problem by using a switch
statement for the string conversion of A2DP connection states.
Bug 1061219: Don't protect |ConvertAttributeString| by ANDROID_VERSION, r=shuang

The function |ConvertAttributeString| doesn't depend on the Android
version is is used by generic code in Gecko. Don't protect it by
ANDROID_VERSION.