Relicence all source and header files included in LGPL code

All code included in libcommon-lgpl.a should be LGPL. Some were licensed
as GPLv2 by mistake. We need to relicense those.

EfficiOS owns the copyright to all of the affected source files and
agrees to this relicensing from GPLv2 to LGPLv2.1.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ib4aa1a7cc8a6f8e2a9891f1bd05c7ea2f8530e9b