wrjpgcom: Fix comment typo

Comment was copied/pasted from skip_variable() without making the
necessary modifications.

wrjpgcom.c

@@ -247,7 +247,7 @@ copy_variable (void)
   if (length < 2)
     ERREXIT("Erroneous JPEG marker length");
   length -= 2;
-  /* Skip over the remaining bytes */
+  /* Copy the remaining bytes */
   while (length > 0) {
     write_1_byte(read_1_byte());
     length--;