Merge branch 'hotfix/1.25.15' into stable
recognize new OpenIndiana release illumos, fix #2584
link gem only when not already available, fix #2586, also small cleaning
do not check libffi-devel on Redhat 6+ if not available, fix #2583
make sure proper ruby path is passed to rubygems_setup, fix #2586
use newer version of rvm gem
break long line in __rvm_initial_gemsets_create
unify tracing, update #2582
eliminate grepping from scripts/rvm, update #2582
add duplicate __rvm_cli_enable_trace to scripts/initialize, update #2582
extract ruby path check in scripts/rvm
eliminate __rvm_cli_enable_trace, update #2582
promote the omnios checks to be used also on openindiana, closes #2588
improve warning when rvm loading missing in shell initialization files, fix #2590
remove the no-op alias_after_create_default, update #2581
improved creating aliases, update #2581
use __rvm_db_ instead of running subprocess for recording ruby, update #2581
remove unneded touch from removing aliases, update #2581
improve deleting aliases and it's logging, update #2581
update tests for new log files for alias_create, update #2581