Upgrade rspec to latest 2.x version & fix deprecation warnings

Author: sohaibbhatti

method_log.gemspec

@@ -26,5 +26,5 @@ Gem::Specification.new do |s|
   s.add_dependency 'trollop'
 
   s.add_development_dependency 'rake'
-  s.add_development_dependency 'rspec', '~> 2.14.0'
+  s.add_development_dependency 'rspec', '~> 2.0'
 end

spec/commit_spec.rb

@@ -66,8 +66,8 @@ module MethodLog
         repository = Repository.new(repository_path)
         commit = repository.commits.to_a.last
 
-        expect(commit.contains?(source_file)).to be_true
-        expect(commit.contains?(another_source_file)).to be_false
+        expect(commit.contains?(source_file)).to be true
+        expect(commit.contains?(another_source_file)).to be false
       end
 
       it 'makes author available' do