removed 'adler32' key from fastresume, since it was implemented with blocking I/O

src/session_impl.cpp

@@ -2683,22 +2683,24 @@ namespace detail
 
 					TORRENT_ASSERT(*slot_iter == p.index);
 					int slot_index = static_cast<int>(slot_iter - tmp_pieces.begin());
+					const entry* ad = i->find_key("adler32");
+	
+					if (ad && ad->type() == entry::int_t)
+					{
 						unsigned long adler
 							= torrent_ptr->filesystem().piece_crc(
 								slot_index
 								, torrent_ptr->block_size()
 								, p.info);
 
-					const entry* ad = i->find_key("adler32");
-	
 						// crc's didn't match, don't use the resume data
-					if (ad && ad->type() == entry::int_t
-						&& ad->integer() != entry::integer_type(adler))
+						if (ad->integer() != entry::integer_type(adler))
 						{
 							error = "checksum mismatch on piece "
 								+ boost::lexical_cast<std::string>(p.index);
 							return;
 						}
+					}
 
 					tmp_unfinished.push_back(p);
 				}