Description of problem:

When the `all_content` parameter is added to a method it isn't translated into the corresponding `All-Content` header.

Version-Release number of selected component (if applicable):

4.2.0

How reproducible:

Always.


Steps to Reproduce:

1. Run a script like this:

---8<---
# Create the connection to the server:
connection = OvirtSDK4::Connection.new(
  url: 'https://engine42.local/ovirt-engine/api',
  username: 'admin@internal',
  password: '...',
  ca_file: 'ca.pem',
  debug: true,
  log: Logger.new('example.log')
)

# List the virtual machines, with all the optional content:
vms_service = connection.system_service.vms_service
vms = vms_service.list(all_content: true)

# Print some of the optional content:
vms.each do |vm|
  puts(vm.rng_device)
end

# Close the connection to the server:
connection.close
--->8---

2. Run the script.

Actual results:

The `rng_device` attribute is empty, and nothing is printed. Also in the `example.log` the request sent to the server doesn't contain the `All-Content` header:

  GET /ovirt-engine/api/vms?all_content=true HTTP/1.1
  Host: engine42.local
  Authorization: Bearer ...
  User-Agent: RubySDK/4.2.0
  Version: 4
  Content-Type: application/xml
  Accept: application/xml

Expected results:

The `rng_device` should be populated, and the request should contain the `All-Content` header:

  GET /ovirt-engine/api/vms?all_content=true HTTP/1.1
  Host: engine42.local
  Authorization: Bearer ...
  User-Agent: RubySDK/4.2.0
  Version: 4
  Content-Type: application/xml
  Accept: application/xml
  All-Content: true  <--- This should be populated