Try to remove outdated files from the "distribution" folder

Clean directory and keep only the expected files with the current
version.

Otherwise we get strange errors about "duplicate modules" when
building after version was switched.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1915368 13f79535-47bb-0310-9956-ffa450edef68

build.gradle

@@ -236,6 +236,66 @@ subprojects {
         destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}")
 
         doLast {
+            // make sure we do not have distribution jar-files with different versions
+            // in the build-dir as those lead to strange errors about "duplicate modules"
+            // when building java9 JPMS class files ("java9")
+            ant.delete(failOnError: true, verbose: true) {
+                fileset(dir: "../build/dist/maven/${project.archivesBaseName}") {
+                    include(name: '*.jar')
+                    exclude(name: "*${version}.jar")
+                    exclude(name: "*${version}-sources.jar")
+
+                    include(name: '*.jar.asc')
+                    exclude(name: "*${version}.jar.asc")
+                    exclude(name: "*${version}-sources.jar.asc")
+
+                    include(name: '*.jar.sha256')
+                    exclude(name: "*${version}.jar.sha256")
+                    exclude(name: "*${version}-sources.jar.sha256")
+
+                    include(name: '*.jar.sha512')
+                    exclude(name: "*${version}.jar.sha512")
+                    exclude(name: "*${version}-sources.jar.sha512")
+
+                    include(name: '*.pom')
+                    exclude(name: "*${version}.pom")
+
+                    include(name: '*.pom.asc')
+                    exclude(name: "*${version}.pom.asc")
+                }
+            }
+            // use failOnError=false for -javadoc and -tests as not all modules create this directory
+            ant.delete(failOnError: false, verbose: true) {
+                fileset(dir: "../build/dist/maven/${project.archivesBaseName}-javadoc") {
+                    include(name: '*-javadoc.jar')
+                    exclude(name: "*${version}-javadoc.jar")
+
+                    include(name: '*-javadoc.jar.asc')
+                    exclude(name: "*${version}-javadoc.jar.asc")
+
+                    include(name: '*-javadoc.jar.sha256')
+                    exclude(name: "*${version}-javadoc.jar.sha256")
+
+                    include(name: '*-javadoc.jar.sha512')
+                    exclude(name: "*${version}-javadoc.jar.sha512")
+                }
+            }
+            ant.delete(failOnError: false, verbose: true) {
+                fileset(dir: "../build/dist/maven/${project.archivesBaseName}-tests") {
+                    include(name: '*-tests.jar')
+                    exclude(name: "*${version}-tests.jar")
+
+                    include(name: '*-tests.jar.asc')
+                    exclude(name: "*${version}-tests.jar.asc")
+
+                    include(name: '*-tests.jar.sha256')
+                    exclude(name: "*${version}-tests.jar.sha256")
+
+                    include(name: '*-tests.jar.sha512')
+                    exclude(name: "*${version}-tests.jar.sha512")
+                }
+            }
+
             ant.checksum(file: it.archivePath, algorithm: 'SHA-256', fileext: '.sha256', format: 'MD5SUM')
             ant.checksum(file: it.archivePath, algorithm: 'SHA-512', fileext: '.sha512', format: 'MD5SUM')
         }