Merge branch 'hotfix/1.26.4'
extract configuring centos for libyaml + empty redhat wrapper
move checking if centos libyaml-devel package is available to common function
extract error message for missing centos libyaml-devel + improved handling
initial take at rhn-channel as source of libyaml-devel
script to sign releases
Use the configured rvm_ruby_repo_branch when fetching Ruby source

This will ensure that specification of a custom branch (e.g. `rvm install
--branch testbranch jruby-head`) will checkout and build the appropriate branch
from source

Fixes #3195
improved output in sign-releases.sh
filter out only variables starting with rvm_old_ in __rvm_unset_exports, fix #3185
use tee instead of mv to force proper certificate permissions
Merge pull request #3168 from wayneeseguin/bugfix/gh_3168_fix_certificates_permissions

fix osx certificate permissions
do not try manually compile yaml on redhat
do not error out when optional redhat repositories are enabled
install libffi-devel always on centos likes
move checking centos libyaml repositories to before action
set user of file in __rvm_sed_i, fix #3200
simplified statf, update #3200
run autopudate after initializing environment in rvm cli, fix #3202
remove the check for requirement of libyaml-devel when running reporsitories installation on centos
Revert "remove the check for requirement of libyaml-devel when running reporsitories installation on centos"

This reverts commit 00f5cb52c801112224628f5ce33c9f8f43058c04.