keep a separate lockfile for ruby 2.4 for now

Change-Id: If8ebd836905c389422fb06e3e2f5d7ce153ea832
Reviewed-on: https://gerrit.instructure.com/100608
Tested-by: Jenkins
Reviewed-by: Tyler Pickett <tpickett@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>

.gitignore

@@ -33,7 +33,9 @@ app/stylesheets/brandable_css_brands
 /db/*sql
 /exports/
 Gemfile.lock
-Gemfile.lock5
+Gemfile.lock.24
+Gemfile.lock.5
+Gemfile.lock.24.5
 /log/
 mkmf.log
 /node_modules

Gemfile.d/_before.rb

@@ -34,11 +34,14 @@ else
 end
 
 # force a different lockfile for rails 5
-unless CANVAS_RAILS4_2
+if !CANVAS_RAILS4_2 || RUBY_VERSION >= '2.4'
   Bundler::SharedHelpers.class_eval do
     class << self
       def default_lockfile
-        Pathname.new("#{Bundler.default_gemfile}.lock5")
+        lockfile = "#{Bundler.default_gemfile}.lock"
+        lockfile << ".24" if RUBY_VERSION > '2.4'
+        lockfile << ".5" unless CANVAS_RAILS4_2
+        Pathname.new(lockfile)
       end
     end
   end