Correction for when ISC_USER envvar is not defined.

Author: asfernandes

src/fbjava-impl/src/main/java/org/firebirdsql/fbjava/impl/DbPolicy.java

@@ -74,7 +74,7 @@ static void databaseOpened() throws SQLException
 				assert securityDb == null;
 
 				securityDb = (FBConnection) DriverManager.getConnection(
-					"jdbc:firebirdsql:embedded:" + securityDatabase + "?charSet=UTF-8");
+					"jdbc:firebirdsql:embedded:" + securityDatabase + "?charSet=UTF-8", "SYSDBA", null);
 				securityDb.setAutoCommit(false);
 				securityDb.setReadOnly(true);