Fix a NullPointerException that occurs with some PPTs now but did not in POI 3.13

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1724487 13f79535-47bb-0310-9956-ffa450edef68

src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFTextParagraph.java

@@ -600,8 +600,15 @@ public final class HSLFTextParagraph implements TextParagraph<HSLFShape,HSLFText
         boolean hasColor = getFlag(ParagraphFlagsTextProp.BULLET_HARDCOLOR_IDX);
         if (tp == null || !hasColor) {
             // if bullet color is undefined, return color of first run
-            if (_runs.isEmpty()) return null;
+            if (_runs.isEmpty()) {
+                return null;
+            }
+            
             SolidPaint sp = _runs.get(0).getFontColor();
+            if(sp == null) {
+                return null;
+            }
+            
             return DrawPaint.applyColorTransform(sp.getSolidColor());
         }