Turns out nil is a valid cpi_api_version, the bosh

looks for info command to determine cpi_api_version,
so on first call it is nil, this will cause error on
info rpc call that then causes BOSH to uses cpi_api_version = 1
which tne causes cascading effect as info rpc is called at
beginning of all cpi commands. Nil is considered a value
in ruby so we don't get default of 1, then we raise error on info call

src/bosh_azure_cpi/lib/cloud/azure/cloud.rb

@@ -23,7 +23,7 @@ class Cloud < Bosh::Cloud
     #
     # @param [Hash] options cloud options
     def initialize(options, api_version = 1)
-      cloud_error("Invalid api_version '#{api_version}'") unless [1, 2].include?(api_version)
+      cloud_error("Invalid api_version '#{api_version}'") unless [1, 2, nil].include?(api_version)
 
       options_dup = options.dup.freeze
 

src/bosh_azure_cpi/spec/unit/cloud/cloud_spec.rb

@@ -53,16 +53,6 @@
           end
         end
 
-        context 'to api version nil' do
-          let(:api_version) { nil }
-
-          it 'raises an exception' do
-            expect do
-              mock_cloud(nil, api_version)
-            end.to raise_error(Bosh::Clouds::CloudError, "Invalid api_version '#{api_version}'")
-          end
-        end
-
         context 'to api version 3' do
           let(:api_version) { 3 }