Underscore should be escaped

[dschuermann]

The underscore poses problem when compiling and should be preceded by a backslash.

\MESSAGE{1}{2}{DNS}{82 Standard query SRV _sip._udp.operateur.fr}{}{0}

should be : \MESSAGE{1}{2}{DNS}{82 Standard query SRV _sip._udp.operateur.fr}{}{0}