qemu-common.h: update copyright date to 2018

Currently the copyright date is set to 2017. Update the date to say
2018.
Signed-off-by: NJohn Arbuckle <programmingkidx@gmail.com>
Reviewed-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NThomas Huth <thuth@redhat.com>

include/qemu-common.h

@@ -17,7 +17,7 @@
 #define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
 
 /* Copyright string for -version arguments, About dialogs, etc */
-#define QEMU_COPYRIGHT "Copyright (c) 2003-2017 " \
+#define QEMU_COPYRIGHT "Copyright (c) 2003-2018 " \
     "Fabrice Bellard and the QEMU Project developers"
 
 /* Bug reporting information for --help arguments, About dialogs, etc */