mkrepo.sh: make sure Packages files are properly sorted

Works around the base system installation failure (the error happens only
with Ubuntu 14.04). Note that the Packages files on Debian/Ubuntu mirrors
are sorted (alphabetically).

Change-Id: I20262e14b90010a67e7fc1d16843313481d0d6a7
Added fuel-agent package

Thist package is supposed to be used for
image based provisioning.

Implements: blueprint image-based-provisioning
Change-Id: I29d0cd7bc850421fc57c84b02c59c8b2285f859d
Merge "mkrepo.sh: make sure Packages files are properly sorted"
Merge "Added fuel-agent package"