[rubygems/rubygems] Don't use util_installer for user install
util_installer
It is not nice to require install directory to be always specified, while this option is later ignored for user installed gems.
Actually, the next step will be to remove check_install_dir check and let the install dir override the user install.
check_install_dir
https://github.com/rubygems/rubygems/commit/beb79e929f
[rubygems/rubygems] Don't use
util_installerfor user installIt is not nice to require install directory to be always specified,
while this option is later ignored for user installed gems.
Actually, the next step will be to remove
check_install_dircheck andlet the install dir override the user install.
https://github.com/rubygems/rubygems/commit/beb79e929f