Remove conf/vm2/source.lua from installed files

[edigiacomo]

conf/vm2/source.lua is installed in /etc/arkimet/vm2/source.lua, but it should be used only during testing:

$ git grep source.lua
arki/runtest:export METEO_VM2_SOURCE="$TOP_SRCDIR/conf/vm2/source.lua"
conf/Makefile.am:       vm2/source.lua
conf/meson.build:install_data('vm2/source.lua', install_dir: conf_dir / 'vm2')
run-local:export METEO_VM2_SOURCE="$TOP_SRCDIR/conf/vm2/source.lua"
run-local.in:export METEO_VM2_SOURCE="@top_srcdir@/conf/vm2/source.lua"

[edigiacomo]

Fixed in d0285e2