In install_lib.pl, no need to Config->import for the relocatableinc setup.

In install_lib.pl, no need to Config->import for the relocatableinc setup.

require Config; within the BEGIN block instead of using it outside it to
save creating one implicit BEGIN block, and running its import twice.

Remove the require 5.004; as the require of Config will fail if running
with anything other than the version about to be installed.

Note in installperl and installman that install_lib.pl imports Config.