Minor fixes,

Fix: fixed the presence of snort in a literal warning the users about
     the plugin beeing build without proper database support.

Fix: fixed endianess return value of some error cases in
     int CheckDBVersion(DatabaseData * data)

Esthetic: Rewrote a condition check in dbProcessSignatureInformation(),
          has no impact on evaluation of the if statement.

Fix: compile of spo_alert_fwsam with --enable-debug and --enable-ipv6

Fix: comparaison betwen reference that could lead to duplicate entries
     if lookup string is contained within lookup string.