patch 9.0.0315: shell command is displayed in message window

Problem:    Shell command is displayed in message window.
Solution:   Do not echo the shell command in the message window.

src/ex_cmds.c

@@ -1011,6 +1011,7 @@ do_bang(
     if (addr_count == 0)		// :!
     {
 	// echo the command
+	dont_use_message_window();
 	msg_start();
 	msg_putchar(':');
 	msg_putchar('!');

src/message.c

@@ -1472,7 +1472,7 @@ msg_start(void)
     }
 
 #ifdef FEAT_EVAL
-    if (need_clr_eos || p_ch == 0)
+    if (need_clr_eos || use_message_window())
     {
 	// Halfway an ":echo" command and getting an (error) message: clear
 	// any text from the command.
@@ -1508,8 +1508,9 @@ msg_start(void)
 #endif
 	    0;
     }
-    else if (msg_didout || p_ch == 0)	    // start message on next line
+    else if (msg_didout || use_message_window())
     {
+	// start message on next line
 	msg_putchar('\n');
 	did_return = TRUE;
 	if (exmode_active != EXMODE_NORMAL)

src/version.c

@@ -707,6 +707,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    315,
 /**/
     314,
 /**/