dist/debian: run update-ca-certificates to avoid security exception on Ubuntu 18.04
dist/debian: run update-ca-certificates to avoid security exception on Ubuntu 18.04

On Ubuntu 18.04 build fails by java.security.InvalidAlgorithmParameterException,
while downloading .pom file from HTTPS URL.
Looks like it's ca-certs problem, can fix by running update-ca-certificates.

Fixed #52

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>
Message-Id: <20180601092954.28319-1-4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>

scylladb/scylla-jmx,scylladb/scylla-jmx,scylladb/scylla-jmx