build: Unify PACKAGE_VERSION on autotools, scons and Android

This patch unifies mesa's PACKAGE_VERSION on autotools, scons and
Android build systems.

Current behaviour is:
 - Autotools uses 9.2.0 as PACKAGE_VERSION
 - Scons and Android use 9.2-devel as PACKAGE_VERSION

With this patch all three build systems use 9.2.0-devel as
PACKAGE_VERSION.

Reviewed-by: Brian Paul <brianp@vmware.com>
build: Use PACKAGE_VERSION from autoconf

Both variables had the same value.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>