Symlink /system/lib/libGLESv3.so -> libGLESv2.so

The platform has a unified GLES2/GLES3 wrapper in libGLESv2.so, which
is what bundled binaries should link against. The NDK will have
separate GLES2 and GLES3 libraries so that applications will get a
link error if they accidentally use GLES3 entry points in a GLES2
application. This symlink allows GLES3 NDK apps to load using the
unified wrapper.

Change-Id: Ic344ef63c334047fccebb55b7cb2fb23a4c2d61b