VERSION: bump version to 2.6.1-rc2

Update version to 2.6.1-rc2.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/VERSION b/VERSION
index 07b2520..1b5558e 100644
--- a/VERSION
+++ b/VERSION
@@ -2,4 +2,4 @@
 VERSION_MINOR = 6
 PATCHLEVEL = 1
 VERSION_TWEAK = 0
-EXTRAVERSION = rc1
+EXTRAVERSION = rc2