ftp: remove PASS pattern for protocol detection

As FTP must have USER before PASS command
unlike IRC which can begin by PASS command

Ticket: 2978

src/app-layer-ftp.c

@@ -966,10 +966,6 @@ static int FTPRegisterPatternsForProtocolDetection(void)
         return -1;
     }
 
-    if (SCAppLayerProtoDetectPMRegisterPatternCI(
-                IPPROTO_TCP, ALPROTO_FTP, "PASS ", 5, 0, STREAM_TOSERVER) < 0) {
-        return -1;
-    }
     if (SCAppLayerProtoDetectPMRegisterPatternCI(
                 IPPROTO_TCP, ALPROTO_FTP, "PORT ", 5, 0, STREAM_TOSERVER) < 0) {
         return -1;