automake: include only one copy VERSION in tarball

The VERSION file is tracked by git (git ls-files), thus
adding it to EXTRA_FILES will result in a duplicate copy
within the final tarball.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72230
Cc: "10.0" <mesa-stable@lists.freedesktop.org>
Reported-by: Patrick Steinhardt <ps@pks.im>
Tested-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

Makefile.am

@@ -36,7 +36,6 @@ PACKAGE_NAME = MesaLib-$(PACKAGE_VERSION)
 EXTRA_FILES = \
 	aclocal.m4					\
 	configure					\
-	VERSION					\
 	bin/ar-lib					\
 	bin/compile					\
 	bin/config.sub					\