engine: masterlist: replace master server domain by mentality.rip

It is essentially the same as ms.xash.su but due to current situation, it is known to be blocked on some Ukrainian ISPs.

ms2.xash.su is retired for now.

engine/common/masterlist.c

@@ -254,6 +254,5 @@ void NET_InitMasters( void )
 
 	// keep main master always there
 	NET_AddMaster( MASTERSERVER_ADR, false );
-	NET_AddMaster( MASTERSERVER_ADR2, false );
 	NET_LoadMasters( );
 }

engine/common/netchan.h

@@ -69,8 +69,7 @@ GNU General Public License for more details.
 //  bytes will be stripped by the networking channel layer
 #define NET_MAX_MESSAGE		PAD_NUMBER(( NET_MAX_PAYLOAD + HEADER_BYTES ), 16 )
 
-#define MASTERSERVER_ADR		"ms.xash.su:27010"
-#define MASTERSERVER_ADR2		"ms2.xash.su:27010"
+#define MASTERSERVER_ADR		"mentality.rip:27010"
 #define MS_SCAN_REQUEST		"1\xFF" "0.0.0.0:0\0"
 
 #define PORT_MASTER			27010