dist/debian: fix missing --configfile parameter on pdebuild
dist/debian: fix missing --configfile parameter on pdebuild

We need to specify --configfile on pdebuild too, otherwise we will
always fail to build .deb on newly created build environment.
Only reason why we still able to build .deb is we already copied
.pbuilderrc to home directory on existing build environment.

Fixes #3456

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>
Message-Id: <20180523204112.24669-1-4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>

avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,duarten/scylla,duarten/scylla