Improve rbenv version detection logic

Author: bshand

lib/ndr_dev_support/capistrano/install_ruby.rb

@@ -53,7 +53,7 @@
 echo ----;
 
         set -e;
-        if ! rbenv versions --bare 2> /dev/null | grep -qF ^#{version}$; then
+        if ! rbenv versions --bare 2> /dev/null | grep -q ^#{Regexp.escape(version)}$; then
           echo Installing ruby #{version};
           { while true; do sleep 20; echo -n '.'; done & } 2> /dev/null;
           sudo -i -n -u #{fetch(:application_user)} sh -c "