[update] update to upstream to version 1.6.20
Squashed 'dbus/' changes from f4606cf..370b2aa

370b2aa bump version
7100a39 Prepare embargoed security release
cab1c56 CVE-2014-3477: deliver activation errors correctly, fixing Denial of Service
4f1ed05 NEWS
03aeacc fixed memory freeing if error during listing services
c9ebd60 NEWS
7c00ed2 make_and_run_test_nodes: avoid undefined behaviour
ba7b857 Start on 1.6.20

git-subtree-dir: dbus
git-subtree-split: 370b2aa04677d447d7b0e63c25397ba8b2193f79
Merge commit '2ddd1d07ec6334164f76e8bccd02f6d193534260'

[security] Fixes CVE-2014-3477.

Signed-off-by: Marko Saukko <marko.saukko@jolla.com>
[init] Sync the dbus.socket with similar things done for dbus.service in commit af05714adaa77417741c375af76b8776a12adcac

Signed-off-by: Marko Saukko <marko.saukko@jolla.com>