rhel page only for rhel

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>

docs/sources/installation/rhel.rst

@@ -4,8 +4,8 @@
 
 .. _rhel:
 
-Red Hat Enterprise Linux / CentOS
-=================================
+Red Hat Enterprise Linux 
+========================
 
 .. include:: install_header.inc