Fixed compiler warnings from connect engine

- clang complains about register in C++
- Removed not used variables
- Fixed bug when printing date in filamdbf.cpp
- Added {} to fix warning about dangling else
- Changed connect_done_func() to be global to remove conflict with header
  files
- Added extra () around assignment in if

storage/connect/tabmysql.cpp

@@ -246,7 +246,7 @@ bool MYSQLDEF::ParseURL(PGLOBAL g, char *url, bool b)
       // Found that if the string is:
       // user:@hostname:port/db/table
       // Then password is a null string, so set to NULL
-			if ((pwd[0] == 0))
+			if (pwd[0] == 0)
 				Password = NULL;
 			else
 				Password = pwd;