Merge branch 'hotfix/1.26.4' into stable
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
merge #3201: Use the configured rvm_ruby_repo_branch when fetching Ruby source
move using rvm_ruby_repo_branch higher up to restore the head to master transformation
Merge branch 'issues/3195-custom-branch'
add warning for unset GEM_HOME/GEM_PATH wen PATH is set for rvm, update #3212
transform GEM_HOME check to an if
just formating
add a warning on RVM Ruby in PATH without GEM_HOME
Merge feature/gh_3212_warn_on_rvm_ruby_in_path_without_gem_home, update \#3212
use full mpapis key fingerprint
merge #3215: use full mpapis key fingerprint, closes #3214
1.26.5
Merge branch 'master' into hotfix/1.26.5
Merge branch 'hotfix/1.26.5'
fix the displayed upload target on github in sign-releases.sh