remove all dependecy on instructure-oauth

this conflicts with the regular oauth gem, and was causing an issue
running `rake db:initial_setup` under bundler 1.15

fixes CNVS-38116

test plan:
- with bundler 1.15.1
- run rake db:initial_setup
- it should work

Change-Id: Idfd83d8cb589a191807125749eaede4de239f9ff
Reviewed-on: https://gerrit.instructure.com/118509
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins
Product-Review: Simon Williams <simon@instructure.com>
QA-Review: Simon Williams <simon@instructure.com>

app/controllers/lti_api_controller.rb

@@ -17,7 +17,7 @@
 #
 
 require 'oauth'
-require 'oauth/client/action_pack'
+require 'oauth/request_proxy/action_controller_request'
 require 'nokogiri'
 
 class LtiApiController < ApplicationController

gems/linked_in/linked_in.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "oauth-instructure", "0.4.10"
+  spec.add_dependency "oauth"
   spec.add_dependency "nokogiri"
 
   spec.add_development_dependency "bundler", "~> 1.5"

gems/lti_outbound/lti_outbound.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency 'i18n', '~> 0.7.0'
-  spec.add_dependency 'oauth-instructure', '0.4.10'
+  spec.add_dependency 'oauth'
 
   spec.add_development_dependency 'bundler', '~> 1.5'
   spec.add_development_dependency 'rake'

gems/twitter/twitter.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_dependency "html_text_helper"
-  spec.add_dependency "oauth-instructure"
+  spec.add_dependency "oauth"
 
   spec.add_development_dependency "bundler", "~> 1.5"
   spec.add_development_dependency "rake"