Fix horizon config under Apache 2.4

Apache 2.4 now uses mod_authz_host for acces control. Horizon's
Apache config needs an update to allow access to its directory,
otherwise a 403 will be returned.
This change replaces a similar previous fixes done for Fedora 18
and Ubuntu 13.10, since this is an Apache version issue, not a
distro-specific one.

Change-Id: Iecc17600d8e1aae6a7b0929b1493d712c307616f
Closes-Bug: #1243075
Fix FROM_PACKAGE checks for novnc and spice

The logic for installing novnc and spice from packages is broken,
which makes it impossible to install from git, which makes bug
1248923 more serious.

Change-Id: I9ae722a5470a16555bca9018da342485f6d3e896
Related-Bug: 1248923
Merge "Fix horizon config under Apache 2.4"
Merge "Fix FROM_PACKAGE checks for novnc and spice"
Bump SWIFT_LOOPBACK_DISK_SIZE_DEFAULT over swift max_file_size

Swift is returning 50x error codes because its disk is too small, set
size bigger then max_file_size in an attempt to fix the problem, or at
least reduce it.

"we create a 4GB device, but swift thinks it can write 5GB, hence fail"
--sdague

This patch based off of Iccd6368e4df71abb5ccfe7d361c64d86e1071d35

Change-Id: Ib56a98cd74e7edf1fa90facc25c72632d43180f1
Related-Bug: #1225664