.travis.yml: support testing non-service build too
.travis.yml: support testing non-service build too

So far, RAUC supports being built with or without servie enabled.
This has a lot of impact on the resulting binaries that are either built
with a D-Bus API or direct method calls.

Thus we should also test the non-service case in CI too which requires
RAUC to be configured differently.

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

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