openvpn: String returned from openvpn is not null-terminated

wireshark shows strings returned by OpenVPN management interface as an
aswer to "state" cmd contain no null character at the end. As a
consequence, osmo_strlcpy cannot be used since it calls strlen() on the
source.
Probably previous implementation was harmless because we zero-fill msgb
buffers prior to filling them.

Change-Id: I4356dc08324a6d877c9e8112306570aabbf6e777
1 file changed