deb: Add ICINGA_BUILD_CLEANUP flag

icinga-build-deb-binary

@@ -91,8 +91,10 @@ echo "[ Running Lintian ]"
   lintian | tee ../lintian-binary.log
 ) || [ "${ICINGA_BUILD_IGNORE_LINT}" -eq 1 ]
 
-echo "[ Cleanup Build Directory ]"
-(
-  set -ex
-  rm -rf "${BUILDDIR:?}/${ICINGA_BUILD_PROJECT}/"
-)
+if [ "${ICINGA_BUILD_CLEANUP:=1}" -gt 0 ]; then
+  echo "[ Cleanup Build Directory ]"
+  (
+    set -ex
+    rm -rf "${BUILDDIR:?}/${ICINGA_BUILD_PROJECT}/"
+  )
+fi