Fix race condition by ensuring workspaces for packages are cleaned up before and after builds.

templates/package-stable.xml

@@ -147,5 +147,12 @@ lintian --fail-on=error,warning -EvIL +pedantic *.dsc *.deb;
       </publishers>
     </org.jenkins__ci.plugins.flexible__publish.FlexiblePublisher>
   </publishers>
-  <buildWrappers/>
+  <buildWrappers>
+    <hudson.plugins.ws__cleanup.PreBuildCleanup plugin="ws-cleanup@0.38">
+      <deleteDirs>false</deleteDirs>
+      <cleanupParameter></cleanupParameter>
+      <externalDelete></externalDelete>
+      <disableDeferredWipeout>false</disableDeferredWipeout>
+    </hudson.plugins.ws__cleanup.PreBuildCleanup>
+  </buildWrappers>
 </project>

templates/package-unstable.xml

@@ -147,5 +147,12 @@ lintian --fail-on=error,warning --suppress-tags orig-tarball-missing-upstream-si
       </publishers>
     </org.jenkins__ci.plugins.flexible__publish.FlexiblePublisher>
   </publishers>
-  <buildWrappers/>
+  <buildWrappers>
+    <hudson.plugins.ws__cleanup.PreBuildCleanup plugin="ws-cleanup@0.38">
+      <deleteDirs>false</deleteDirs>
+      <cleanupParameter></cleanupParameter>
+      <externalDelete></externalDelete>
+      <disableDeferredWipeout>false</disableDeferredWipeout>
+    </hudson.plugins.ws__cleanup.PreBuildCleanup>
+  </buildWrappers>
 </project>