Debugger: Fix a warning

Followup to 01006580



Change-Id: I4acd54472df03c019493426303d5a52a9902f9fd
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/debuggerprotocol.cpp

@@ -267,7 +267,7 @@ static QByteArray ind(int indent)
 
 void GdbMi::dumpChildren(QByteArray * str, bool multiline, int indent) const
 {
-    for (size_t i = 0; i < m_children.size(); ++i) {
+    for (int i = 0; i < m_children.size(); ++i) {
         if (i != 0) {
             *str += ',';
             if (multiline)