Fix Uninitialized constant Handsoap verify ESXi

Fix the uninitialized constant Handsoap failure when verifying host
credentials.

```
ERROR -- evm: MIQ(host_controller-update): uninitialized constant ManageIQ::Providers::Vmware::InfraManager::HostEsx::Handsoap
```

Author: agrare

app/models/manageiq/providers/vmware/infra_manager/host_esx.rb

@@ -144,6 +144,7 @@ def vim_advanced_settings
   def verify_credentials_with_ws(auth_type = nil)
     raise "No credentials defined" if self.missing_credentials?(auth_type)
 
+    require "handsoap"
     begin
       with_provider_connection(:use_broker => false, :auth_type => auth_type) {}
     rescue SocketError, Errno::EHOSTUNREACH, Errno::ENETUNREACH => err