Update %install secion of librdmacm spec file

Update %install secion of librdmacm spec file

Change from using the %makeinstall macro to using "make install"
directly.  The page <http://fedoraproject.org/wiki/Packaging/Guidelines>
has this to say:

  "Fedora's RPM includes a %makeinstall macro but it must NOT be used
   when make install DESTDIR=%{buildroot} works. %makeinstall is a
   kludge....
   It is error-prone and can have unexpected effects....
   It can trigger unnecessary and wrong rebuilds....
   ....it can cause broken *.la files to be installed....
   Instead, Fedora packages should use: make DESTDIR=%{buildroot}
   install or make DESTDIR=$RPM_BUILD_ROOT install"

The librdmacm package uses automake, which means that the "make
DESTDIR=... install" method works fine, so we should use it.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>