Install dir for CentOS 6 - 64

[ctradu]

On CentOS the install directories for erlang modules are:
32 bits: /usr/lib/erlang/lib/
64 bits: /usr/lib64/erlang/lib/

The problem is that LIB_DIR is constructed in a way that lib is always added before erlang/lib :

libdir       = ${exec_prefix}/lib
LIB_DIR      = ${libdir}/erlang/lib/$(APPNAME)-$(VERSION)

This problem appears on centos 6 / 64bits
On other systems the paths may be different.