Install: Improves ruby/rvm install - Directly install the right version

The script used to download the latest version of ruby through rvm, then
later on install the one used by the project. Now we directly download
the version of the project when rvm is installed.

scripts/create-dev-env.sh

@@ -349,6 +349,11 @@ if [ "$HOME/.rvm" != $RUBY_DIR ]; then
   fi
 fi
 
+# Let the repo override the version of Ruby to install
+if [[ -r $BASE/edx-platform/.ruby-version ]]; then
+  RUBY_VER=`cat $BASE/edx-platform/.ruby-version`
+fi
+
 # rvm has issues in debian family, this is taken from stack overflow
 case `uname -s` in
     Darwin)
@@ -361,7 +366,7 @@ case `uname -s` in
                 http://stackoverflow.com/questions/9056008/installed-ruby-1-9-3-with-rvm-but-command-line-doesnt-show-ruby-v/9056395#9056395"
         sudo apt-get --purge remove ruby-rvm
         sudo rm -rf /usr/share/ruby-rvm /etc/rvmrc /etc/profile.d/rvm.sh
-        curl -sL https://get.rvm.io | bash -s stable --ruby --autolibs=enable --auto-dotfiles
+        curl -sSL https://get.rvm.io | bash -s stable --ruby=$RUBY_VER --autolibs=enable --auto-dotfiles
     ;;
 esac
 
@@ -386,11 +391,6 @@ case `uname -s` in
         ;;
 esac
 
-# Let the repo override the version of Ruby to install
-if [[ -r $BASE/edx-platform/.ruby-version ]]; then
-  RUBY_VER=`cat $BASE/edx-platform/.ruby-version`
-fi
-
 # Current stable version of RVM (1.19.0) requires the following to build Ruby:
 #
 # autoconf automake libtool pkg-config libyaml libxml2 libxslt libksba openssl