avoid returning empty MySQLWarnings in odd edge case scenario

Author: rubensayshi

AUTHORS

@@ -49,6 +49,7 @@ Xiangyu Hu <xiangyu.hu at outlook.com>
 Xiaobing Jiang <s7v7nislands at gmail.com>
 Xiuming Chen <cc at cxm.cc>
 Zhenye Xie <xiezhenye at gmail.com>
+Ruben de Vries <ruben at rubensayshi.com>
 
 # Organizations
 

errors.go

@@ -122,6 +122,10 @@ func (mc *mysqlConn) getWarnings() (err error) {
 			warnings = append(warnings, warning)
 
 		case io.EOF:
+			if len(warnings) == 0 {
+				return nil
+			}
+
 			return warnings
 
 		default: