Cleanup: Automake: remove single use variables

Cleanup: Automake: remove single use variables

Throughout the Automake files, there is a consistent pattern somewhat
like this:

    FOO_BINS = ....

    sbin_PROGRAMS += $(FOO_BINS)

This commit all such patterns whenever the variable is not used anywhere
else and appends to the target directly.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>