Make sure unittest/user/config/soffice.cfg/ exits

...otherwise PresetHandler::getOrCreateRootStorageShare
(framework/source/accelerators/presethandler.cxx) will cause a
com.sun.star.io.IOException: "URL
"file:///.../solver/unxlngx6/unittest/user/config/soffice.cfg" passed to
css.embed.FileSystemStorageFactory.createInstanceWithArguments does not denote
an existing directory" in some CppunitTests.  (And
1eecb8df "Some cleanup and consolidation of the
Impress layout work" removed the last file that got definitely created in that
directory from test/Package_unittest.mk.)

Change-Id: Idbe42fdd6b06194781cceef62c50531ce0e1c706

test/Package_unittest.mk

@@ -18,6 +18,7 @@ $(eval $(call gb_Package_add_file,test_unittest,unittest/user/autotext/en-US/tem
 $(eval $(call gb_Package_add_file,test_unittest,unittest/user/autotext/en-US/standard.bau,user/autotext/en-US/standard.bau))
 $(eval $(call gb_Package_add_file,test_unittest,unittest/user/autotext/en-US/crdbus50.bau,user/autotext/en-US/crdbus50.bau))
 $(eval $(call gb_Package_add_file,test_unittest,unittest/user/config/psetup.xpm,user/config/psetup.xpm))
+$(eval $(call gb_Package_add_file,test_unittest,unittest/user/config/soffice.cfg/.dummy,empty-directory-dummy))
 $(eval $(call gb_Package_add_file,test_unittest,unittest/install/share/config/soffice.cfg/simpress/transitions.xml,user/config/soffice.cfg/simpress/transitions.xml))
 $(eval $(call gb_Package_add_file,test_unittest,unittest/install/share/config/soffice.cfg/simpress/transitions-ogl.xml,user/config/soffice.cfg/simpress/transitions-ogl.xml))
 $(eval $(call gb_Package_add_file,test_unittest,unittest/install/share/config/soffice.cfg/simpress/effects.xml,user/config/soffice.cfg/simpress/effects.xml))