JFrog Speedup

The current method of downloading artifacts for the daily repo generation
is to use a 'build :: build number' style search.  It turns out this
is actually not effective as it performs a full artifactory scan to
get content.  Instead if we directly ask for the content from the path,
the files we want are downloaded very quickly and no load is placed on
the artifactory server.

Change-Id: I1095b784dee73782d3104f301c977a7d958cce00
Signed-off-by: Mark Beierl <mark.beierl@canonical.com>