Don't do a check inside an AC_MSG_CHECKING/AC_MSG_RESULT pair - the

Don't do a check inside an AC_MSG_CHECKING/AC_MSG_RESULT pair - the
output looks bad if you do.  Split the check for "should I check for an
SNMP library?" into "should I check for NET-SNMP?" and "should I check
for UCD SNMP?" (which makes sense because they're controlled by
different configure script options).

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@8197 f5534014-38df-0310-8fa8-9805f1628bb7