gnunet: update to version 0.16.2

gnunet: update to version 0.16.2

Sync GNUnet package with master branch.
This is a new major release. It breaks protocol compatibility with the
0.15.x versions. Please be aware that Git master is thus henceforth
(and has been for a while) INCOMPATIBLE with the 0.15.x GNUnet network,
and interactions between old and new peers will result in issues.
0.15.x peers will be able to communicate with Git master or 0.16.x
peers, but some services - in particular GNS - will not be compatible.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
(cherry picked from commits
 deafd6cf3f gnunet: update to v0.14.1
 746bb95552 gnunet: update to version 0.15.3
 23b5b516ae gnunet: fix compilation with big endian
 c3c6a2ff1d gnunet: several improvements
 23f722f905 gnunet: packaging fixes
 2f8e696189 gnunet: update to 0.16.1
 f951f61005 gnunet: improve init script
 033744ac59 gnunet: update to 0.16.2
 65f5f850f3 gnunet: work-around sysupgrade restore missing file ownerships
)