Fix possible ArrayIndexOutOfBoundsException seen with some word documents

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1674954 13f79535-47bb-0310-9956-ffa450edef68

src/scratchpad/src/org/apache/poi/hwpf/converter/AbstractWordConverter.java

@@ -850,7 +850,7 @@ public abstract class AbstractWordConverter
             String[] values = cr.getDropDownListValues();
             Integer defIndex = cr.getDropDownListDefaultItemIndex();
 
-            if ( values != null )
+            if ( values != null && values.length > 0 )
             {
                 processDropDownList( currentBlock, cr, values,
                         defIndex == null ? -1 : defIndex.intValue() );