buildroot

domoticz: fix build with boost 1.66

Patch fetch from one of the answer of
 https://github.com/domoticz/domoticz/issues/2034
(issue still opened, no official PR sent upstream)

Boost asio changed its API:
 - http://www.boost.org/doc/libs/1_66_0/doc/html/boost_asio/net_ts.html

Fixes:
 - http://autobuild.buildroot.net/results/5f02c8fc84889748f283ee1cb76248bb0880215a

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>