src/service: give more targeted hint about D-Bus connection failures
src/service: give more targeted hint about D-Bus connection failures

For this we include the type of bus we experience issues with.

Signed-off-by: Enrico Joerns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

jluebbe/rauc,ejoerns/rauc,rauc/rauc,jluebbe/rauc,rauc/rauc,jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc