Make the default test something that works as a non-superuser

Author: palfrey

src/odbc.rs

@@ -159,7 +159,7 @@ mod test {
         connect(
             &Opts::new()
                 .connection_string(postgres_connect())
-                .sql_text("SHOW config_file"),
+                .sql_text("SHOW IS_SUPERUSER"),
         )
         .unwrap();
     }

src/pg.rs

@@ -83,7 +83,7 @@ mod test {
         connect(
             &Opts::new()
                 .connection_string(postgres_connect())
-                .sql_text("SHOW config_file"),
+                .sql_text("SHOW IS_SUPERUSER"),
         )
         .unwrap();
     }