Try moving database/ away in case of failure

src/init.cpp

@@ -605,8 +605,22 @@ bool AppInit2(boost::thread_group& threadGroup)
 
     if (!bitdb.Open(GetDataDir()))
     {
-        string msg = strprintf(_("Error initializing wallet database environment %s!"), strDataDir.c_str());
-        return InitError(msg);
+        // try moving the database env out of the way
+        boost::filesystem::path pathDatabase = GetDataDir() / "database";
+        boost::filesystem::path pathDatabaseBak = GetDataDir() / strprintf("database.%"PRI64d".bak", GetTime());
+        try {
+            boost::filesystem::rename(pathDatabase, pathDatabaseBak);
+            printf("Moved old %s to %s. Retrying.\n", pathDatabase.string().c_str(), pathDatabaseBak.string().c_str());
+        } catch(boost::filesystem::filesystem_error &error) {
+             // failure is ok (well, not really, but it's not worse than what we started with)
+        }
+
+        // try again
+        if (!bitdb.Open(GetDataDir())) {
+            // if it still fails, it probably means we can't even create the database env
+            string msg = strprintf(_("Error initializing wallet database environment %s!"), strDataDir.c_str());
+            return InitError(msg);
+        }
     }
 
     if (GetBoolArg("-salvagewallet"))