wpa-supplicant: add systemd support

* native systemd support came in with v1.0 [1]
* needs [2] to work properly
* mends my wlan under control of networkmanager

[1] http://hostap.epitest.fi/gitweb/gitweb.cgi?p=hostap-1.git;a=blob_plain;f=wpa_supplicant/ChangeLog
[2] http://patches.openembedded.org/patch/34335/



Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>