MAINTAINERS: Update Sean Hefty's email address

My Unix email account is being discontinued at end of Q1 '08.
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

MAINTAINERS

@@ -1919,7 +1919,7 @@ INFINIBAND SUBSYSTEM
 P:	Roland Dreier
 M:	rolandd@cisco.com
 P:	Sean Hefty
-M:	mshefty@ichips.intel.com
+M:	sean.hefty@intel.com
 P:	Hal Rosenstock
 M:	hal.rosenstock@gmail.com 
 L:	general@lists.openfabrics.org