remove the PBX_ODBC logic from the configure script, and add GENERIC_ODCB logic that...

remove the PBX_ODBC logic from the configure script, and add GENERIC_ODCB logic that includes copying the relevant LIB and INCLUDE data from either UnixODBC or iODBC, based on which was found; if both were found, prefer UnixODBC

this stops modules from being linked against both sets of libraries on systems that have both installed

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@168734 65c4cc65-6c06-0410-ace0-fbb531ad65f3