Reset character attributes before start of welcome banner, in case

it's a serial console and remembers state from the previous program
run.

src/hci/shell_banner.c

 	int enter_shell = 0;
 
 	/* Print welcome banner */
-	printf ( "\n\n\n" BOLD "gPXE " VERSION
+	printf ( NORMAL "\n\n\n" BOLD "gPXE " VERSION
 		 NORMAL " -- Open Source Boot Firmware -- "
 		 CYAN "http://etherboot.org" NORMAL "\n"
 		 "Press Ctrl-B for the gPXE command line..." );