scripts/set in rvm-0.1.37 vs scripts/set in rvm-0.1.38

@@ -15,11 +15,11 @@
   exit 1
 fi
 
 # Perform an action using one of a selected ruby's specified binaries.
 __rvm_ruby_do() {
-  __rvm_select
-  __rvm_use
+  # Return on invalid rubies.
+  __rvm_become || return 1
 
   binary="$(echo $action | sed 's#do$##')"
   if [[ -x "$rvm_ruby_home/bin/$binary" ]] ; then
     binary="$rvm_ruby_home/bin/$binary"
   elif [[ -x "$rvm_ruby_global_gems_path/bin/$binary" ]] ; then