Avoid intermittent failure of srcDistZip with parallel builds/tests

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1899163 13f79535-47bb-0310-9956-ffa450edef68

build.gradle

                 exclude '*.docx'
                 exclude '*.pptx'
                 exclude '*.xlsx'
+
+                // exclude intermediate files
+                exclude '**/*-saved.xls'
             }
             from('legal') { exclude 'HEADER' }
         }