Making sure that we will cleanup the write marker after we did the co…

…mplete index cleanup

Raven.Database/Indexing/IndexStorage.cs

@@ -166,6 +166,8 @@ private void OpenIndexOnStartup(DocumentDatabase documentDatabase, string indexN
 
 						CheckIndexAndRecover(directory, indexDirectory);
 						IndexWriter.Unlock(directory);
+						// for some reason, just calling unlock doesn't remove this file
+						directory.DeleteFile("write.lock");
 					}
 				}
 			}