add description of -no_ecdhe option to s_server man page

While the -help message references this option, the man page
doesn't mention the -no_ecdhe option.
This patch fixes this omission.

doc/apps/s_server.pod

@@ -45,6 +45,7 @@ B<openssl> B<s_server>
 [B<-no_ssl3>]
 [B<-no_tls1>]
 [B<-no_dhe>]
+[B<-no_ecdhe>]
 [B<-bugs>]
 [B<-brief>]
 [B<-hack>]
@@ -145,6 +146,11 @@ a static set of parameters hard coded into the s_server program will be used.
 if this option is set then no DH parameters will be loaded effectively
 disabling the ephemeral DH cipher suites.
 
+=item B<-no_ecdhe>
+
+if this option is set then no ECDH parameters will be loaded effectively
+disabling the ephemeral ECDH cipher suites.
+
 =item B<-no_tmp_rsa>
 
 certain export cipher suites sometimes use a temporary RSA key, this option