mesa: Bump version to 10.2-rc2

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
diff --git a/VERSION b/VERSION
index 7b01ee1..827ea06 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-10.2.0-rc1
+10.2.0-rc2