travis: pass proper path to make distcheck
travis: pass proper path to make distcheck

On Travis CI gems are installed into user home directory. If make
distcheck is run under sudo, PATH will be reset and configure won't be
able to find asciidoctor. So let's pass full user's path  to make
distcheck.

Signed-off-by: Dmitry Eremin-Solenikov <05e7612c354c8479a2d1e9b11fb63ce18664b3ca@linaro.org>
Reviewed-by: Bill Fischofer <52f3c909d51cc5d355a68a403df6906b3c1a8f83@linaro.org>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

dkrot/odp,dkrot/odp,dkrot/odp,dkrot/odp