medusa: remove postgresql variant

autoconf does not support pg_config discovery of postgresql and its
paths, a requirement for installation with modern versions of
postgresql.

security/medusa/Portfile

@@ -64,13 +64,6 @@ variant subversion description "Build the Subversion module" {
                     --enable-module-svn=yes
 }
 
-variant postgresql description "Build the PostgreSQL module" {
-    depends_lib-append port:postgresql83
-    configure.args-replace \
-                    --enable-module-postgres=no \
-                    --enable-module-postgres=yes
-}
-
 # FIXME check building afpfs-ng, ncp
 
 livecheck.type      regex