attempt to fix an issue discoverred by jat with sending two close commands back to back will cause an assert to fail

git-svn-id: https://svn.musicpd.org/mpd/trunk@3442 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/interface.c

@@ -319,6 +319,11 @@ static int processBytesRead(Interface * interface, int bytesRead) {
 					interface->bufferLength);
 			interface->bufferPos = 0;
 		}
+		if(ret == COMMAND_RETURN_KILL || ret == COMMAND_RETURN_CLOSE)
+		{
+		    break;
+		}
+
 	}
 
 	return ret;