Fix i#84002 by putting braces when needed

In the case of sqrt with more than 2 operands, like over, we need
to put braces in the beginning and in the end of the element.

Change-Id: I391db14cd2ddc37695fe0b1f590a89b9dd4369ef
Reviewed-on: https://gerrit.libreoffice.org/5153Reviewed-by: Luboš Luňák <l.lunak@suse.cz>
Tested-by: Luboš Luňák <l.lunak@suse.cz>

starmath/source/node.cxx

@@ -1105,7 +1105,14 @@ void SmRootNode::CreateTextFromNode(OUString &rText)
     }
     else
         rText += "sqrt ";
+
+    if (!pExtra && GetSubNode(2)->GetNumSubNodes() > 1)
+        rText += "{ ";
+
     GetSubNode(2)->CreateTextFromNode(rText);
+
+    if (!pExtra && GetSubNode(2)->GetNumSubNodes() > 1)
+        rText += "} ";
 }