remove SSL cipher DHE-RSA-AES128-GCM-SHA256

I830bec497338 says:

"except that DHE and other CPU-expensive ciphers are not enabled"

but DHE-RSA-AES128-GCM-SHA256 was erroneously left in the config 
although it was not usable (given the later !DH directive, and the
absence of the dh_param).

In all respects, this is a no-op

--
Change-Id: I39b389b63ae6b8848abb20431091263717192582