mysqlc: ensure fetched result while invoking last

Change-Id: Ia1872973eefff1d8d677aa443b0c03d3ea569d60
Reviewed-on: https://gerrit.libreoffice.org/65716
Tested-by: Jenkins
Reviewed-by: Tamás Bunth <btomi96@gmail.com>

connectivity/source/drivers/mysqlc/mysqlc_resultset.cxx

@@ -612,6 +612,7 @@ sal_Bool SAL_CALL OResultSet::last()
 {
     MutexGuard aGuard(m_aMutex);
     checkDisposed(OResultSet_BASE::rBHelper.bDisposed);
+    ensureResultFetched();
     m_nRowPosition = m_nRowCount - 1;
 
     return true;