build.xml: squash ant warning about changing classpath
build.xml: squash ant warning about changing classpath

we don't care, actually, that's the intention of it

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb