[ruby] install rvm has error in CentOS

Error running 'requirements_centos_libs_install libffi-devel',

showing last 15 lines of /usr/local/rvm/log/1421736709/package_install_libffi-devel.log

Error: Package: libffi-devel-3.0.5-3.2.el6.i686 (base)'

解法：  

rpm -e --nodeps libffi

And it uninstalled the offending libffi package. Then

yum install libffi-devel