fish_prompt: fix __bobthefish_rvm_info for both rvm installation types (#140)

fish_prompt.fish

@@ -583,8 +583,12 @@ function __bobthefish_rvm_parse_ruby -S -a ruby_string scope -d 'Parse RVM Ruby
 end
 
 function __bobthefish_rvm_info -S -d 'Current Ruby information from RVM'
+  # look for rvm install path
+  set -q rvm_path
+    or set -l rvm_path ~/.rvm /usr/local/rvm
+  
   # More `sed`/`grep`/`cut` magic...
-  set -l __rvm_default_ruby (grep GEM_HOME ~/.rvm/environments/default | sed -e"s/'//g" | sed -e's/.*\///')
+  set -l __rvm_default_ruby (grep GEM_HOME $rvm_path/environments/default | sed -e"s/'//g" | sed -e's/.*\///')
   set -l __rvm_current_ruby (rvm-prompt i v g)
   [ "$__rvm_default_ruby" = "$__rvm_current_ruby" ]; and return