Update .gitignore

Shouldn't have added libs directory.  This is for the pre-compiled native libs.

.gitignore

@@ -71,4 +71,3 @@
 /jme3-android-native/openal-soft/
 /jme3-android-native/OpenALSoft.zip
 /jme3-android-native/stb_image/
-/jme3-android-native/libs/