Increase the buffer size for the completed ODBC connection string

It seems plausible that a completed DSN could be longer than 1KiB as it
may contain more keys than were specified in it originally, so try to
ensure we don't truncate it by increasing the buffer size for it.

src/backends/odbc/session.cpp

@@ -104,7 +104,7 @@ odbc_session_backend::odbc_session_backend(
                               "allocating connection handle");
     }
 
-    SQLCHAR outConnString[1024];
+    SQLCHAR outConnString[4096];
     SQLSMALLINT strLength = 0;
 
     std::string connectString = parameters.get_connect_string();