Use path to locate powershell.exe & remove deps on Windows cookbook

The only reason we use to have a dependency on Windows cookbook was the
locate_sysnative_cmd helper.
However this helper is not a "which" or "where", it just check whether
the given path exist under the "native" system path.
In our case, powershell.exe is not located there, but deeper in the
directory structure, so "powershell.exe" was returned.
So we don't need this helper and the Windows cookbook :)

libraries/base_provider.rb

@@ -24,7 +24,6 @@ module BaseProvider
     require 'yaml'
     require 'base64'
     include Chef::Mixin::ShellOut
-    include Windows::Helper
 
     def self.uri_to_wsus_endpoint_params(uri)
       uri = URI uri
@@ -46,10 +45,6 @@ def endpoint_params
       @endpoint ||= @new_resource.endpoint ? WsusServer::BaseProvider.uri_to_wsus_endpoint_params(@new_resource.endpoint) : ''
     end
 
-    def powershell
-      locate_sysnative_cmd('powershell.exe')
-    end
-
     def powershell_out64(cmd, timeout = 300)
       flags = [
         # Hides the copyright banner at startup.
@@ -70,7 +65,7 @@ def powershell_out64(cmd, timeout = 300)
       # Use powershell with absolute path to the binary (it's the same path for all versions)
       # Use the locate_sysnative helper to target the right powershell binary
       # => https://msdn.microsoft.com/en-us/library/windows/desktop/aa384187.aspx
-      cmd = shell_out "#{powershell} #{flags.join(' ')} -EncodedCommand #{encoded_command}", timeout: timeout
+      cmd = shell_out "powershell.exe #{flags.join(' ')} -EncodedCommand #{encoded_command}", timeout: timeout
       cmd.error!
       raise 'Invalid syntax in PowershellScript' if cmd.stderr && cmd.stderr.include?('ParserError')
       cmd

metadata.rb

@@ -5,7 +5,6 @@
 description      'Installs wsus server'
 version          '2.3.2'
 supports         'windows'
-depends          'windows'
 
 chef_version '>= 12.1'
 source_url 'https://github.com/criteo-cookbooks/wsus-server'