Fix decoder for missing ClearRanges

If the ClearRange mutation happens within the given key prefix space,
previously the mutation is not printed. Fix by checking the prefix range
overlaps with the ClearRange mutation.

fdbbackup/FileDecoder.actor.cpp

@@ -457,7 +457,8 @@ ACTOR Future<Void> process_file(Reference<IBackupContainer> container, LogFile f
 					print = m.param1.startsWith(StringRef(params.prefix));
 				} else if (m.type == MutationRef::ClearRange) {
 					KeyRange range(KeyRangeRef(m.param1, m.param2));
-					print = range.contains(StringRef(params.prefix));
+					KeyRange range2 = prefixRange(StringRef(params.prefix));
+					print = range.intersects(range2);
 				} else {
 					ASSERT(false);
 				}