[PATCH] Export RCS_TAR_IGNORE for rpm targets

The variable RCS_TAR_IGNORE is used in scripts/packaging/Makefile, but not
exported from the main Makefile, so it's never used.

This results in the rpm targets being very unhappy in quilted trees.

Signed-off-by: Tom Rini <trini@kernel.crashing.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>