If a user specifically asks for rdmacm support in configure script and
librdmacm (usual and devel) libraries are not found, configure script
would abort.
If a user didn't specify anything, and rdmacm libraries are not found,
configure script will continue after issuing warning message:
"Please install librdmacm and librdmacm-devel or disable rdmacm support"
-- YK
This commit was SVN r25253.