Fix webapi accountless crash

CHANGELOG.md

@@ -7,6 +7,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 `Added` Security groups support to the OpenVNet integration.
 
+`Fixed` A bug where the WebAPI would crash when no account id was set in a request. It now fails gracefully with a 400 error instead.
+
 `Fixed` A crash that occurred when performing a POST request to the ssh_key_pairs endpoint without including the "public_key" field in the parameters.
 
 `Fixed` A bug in the `lxc-start` command generation, causing LXC instances to crash on startup.

dcmgr/lib/dcmgr/endpoints/12.03/core_api.rb

@@ -56,8 +56,9 @@ class CoreAPI < Sinatra::Base
 
     before do
       requester_account_id = request.env[HTTP_X_VDC_ACCOUNT_UUID]
+
       if requester_account_id.nil?
-        @account = nil
+        raise E::AccountIdNotSet, 'No account id was set in the HTTP headers.'
       else
         begin
           # find or create account entry.

dcmgr/lib/dcmgr/endpoints/errors.rb

@@ -178,5 +178,6 @@ def self.set_error_code_type(error_code, klass)
     define_error(:UnknownEvaluationPeriods, 400, '199')
     define_error(:UnknownNotificationPeriods, 400, '200')
     define_error(:PasswordNotInDatabase, 410, '201')
+    define_error(:AccountIdNotSet, 400, '202')
   end
 end