json: Move switch 'fall through' comment to correct place

Reported by GCC9 when building with CFLAG -Wimplicit-fallthrough=2:

  qobject/json-parser.c: In function ‘parse_literal’:
  qobject/json-parser.c:492:24: error: this statement may fall through [-Werror=implicit-fallthrough=]
    492 |     case JSON_INTEGER: {
        |                        ^
  qobject/json-parser.c:524:5: note: here
    524 |     case JSON_FLOAT:
        |     ^~~~

Correctly place the 'fall through' comment.

Reported-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190719131425.10835-2-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

qobject/json-parser.c

@@ -519,8 +519,8 @@ static QObject *parse_literal(JSONParserContext *ctxt)
             }
             assert(ret == -ERANGE);
         }
-        /* fall through to JSON_FLOAT */
     }
+    /* fall through to JSON_FLOAT */
     case JSON_FLOAT:
         /* FIXME dependent on locale; a pervasive issue in QEMU */
         /* FIXME our lexer matches RFC 8259 in forbidding Inf or NaN,