Move temporary certificate file creation into spec helper

Rakefile

@@ -24,7 +24,6 @@ require 'rspec/core'
 require 'rspec/core/rake_task'
 RSpec::Core::RakeTask.new(:spec) do |spec|
   spec.pattern = FileList['spec/unit/**/*_spec.rb']
-  touch "AzureLinuxCert.pem"
 end
 
 RSpec::Core::RakeTask.new(:functional) do |spec|

spec/spec_helper.rb

@@ -15,6 +15,10 @@ require 'chef/knife/azure_server_create'
 require 'chef/knife/azure_server_describe'
 require 'chef/knife/azure_image_list'
 
+require 'fileutils'
+#Create an empty mock certificate file
+FileUtils.touch('AzureLinuxCert.pem')
+
 def tmpFile filename
   tmpdir = 'tmp'
   Dir::mkdir tmpdir unless FileTest::directory?(tmpdir)