migration: Trivial cleanup save_page_header() on same block check

The 2nd check on RAM_SAVE_FLAG_CONTINUE is a bit redundant.  Use a boolean
to be clearer.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration/ram.c

@@ -689,14 +689,15 @@ static size_t save_page_header(RAMState *rs, QEMUFile *f,  RAMBlock *block,
                                ram_addr_t offset)
 {
     size_t size, len;
+    bool same_block = (block == rs->last_sent_block);
 
-    if (block == rs->last_sent_block) {
+    if (same_block) {
         offset |= RAM_SAVE_FLAG_CONTINUE;
     }
     qemu_put_be64(f, offset);
     size = 8;
 
-    if (!(offset & RAM_SAVE_FLAG_CONTINUE)) {
+    if (!same_block) {
         len = strlen(block->idstr);
         qemu_put_byte(f, len);
         qemu_put_buffer(f, (uint8_t *)block->idstr, len);