From coverity: editor pane font can be null

git-svn-id: http://svn.code.sf.net/p/davmail/code/trunk@2234 3d1905a2-6b24-0410-a738-b14d5a86fcbd

src/java/davmail/ui/AboutFrame.java

@@ -72,7 +72,8 @@ public class AboutFrame extends JFrame {
         jEditorPane = new JEditorPane();
         HTMLEditorKit htmlEditorKit = new HTMLEditorKit();
         StyleSheet stylesheet = htmlEditorKit.getStyleSheet();
-        stylesheet.addRule("body { font-size:small;font-family: " + jEditorPane.getFont().getFamily() + '}');
+        Font font = jEditorPane.getFont();
+        stylesheet.addRule("body { font-size:small;font-family: " + ((font==null)?"Arial":font.getFamily()) + '}');
         jEditorPane.setEditorKit(htmlEditorKit);
         jEditorPane.setContentType("text/html");
         jEditorPane.setText(getContent(null));