This fixes some minor issues with the make files for Java/C++ SDK examples in DevelopersGuide/FirstSteps. For Java examples, an exatra "-f Example_Java.mk" was a leftover from a previous change. For C++ examples, 'make clean' was not working correctly, because of a leftover from a previous change. Both should be fixed now. Change-Id: Id936824675a9bfd43674ca526bc97a998ed9daf8 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/159777 Tested-by: Jenkins Reviewed-by: Hossein <hossein@libreoffice.org>