FreeSWITCH-FS-7269

[6/6] srtp: Rename AUTOMAKE_OPTS to AUTOMAKE_OPTIONS

The latter is a well known automake variable, used
to set (per-Makefile) automake options and supported
since the beginning of time (= automake 1.4).

The former is a made-up variable that doesn't really
do anything.

Signed-off-by: Stefan Knoblich <stkn@openisdn.net>