Don't compile libaapt with the build number

Don't compile libaapt with the build number

Only do that for the aapt binary itself. This will allow libaapt to be
converted to Soong.

Also remove a few lines that weren't doing anything: aaptCppflags was
never set, LOCAL_C_INCLUDES := $(LOCAL_PATH) is implied.

Test: m aapt
Test: aapt version
Change-Id: Ia3bcece14921417e1bfd3406630961c013bd497c