Remove use_single_quotes option from Msf namespace

Internally wrapped lines of powershell built by :cmd_psh_payload
in the Rex namespace require being able to place wrapping quotes
in different logical places for :generate_psh_command_line and
:run_hidden_psh methods. Using single quotes in the Arguments
parameter of the hidden PSH runner and double quotes after the
-Command flag maintains allows us to wrap the outer command in
double quotes, while properly ecaping and wrapping the arguments
parameter for PSH execution in single quotes.

This isn't ideal, in a perfect world we'd be escaping all nested
quotes and escape chars of any type valid for PSH. However, that
would require more manual testing than anyone has time for (now).

Author: RageLtMan

lib/msf/core/exploit/powershell.rb

@@ -18,7 +18,6 @@ def initialize(info = {})
         OptBool.new('Powershell::noninteractive', [true, 'Execute powershell without interaction', true]),
         OptBool.new('Powershell::encode_final_payload', [true, 'Encode final payload for -EncodedCommand', false]),
         OptBool.new('Powershell::encode_inner_payload', [true, 'Encode inner payload for -EncodedCommand', false]),
-        OptBool.new('Powershell::use_single_quotes', [true, 'Wraps the -Command argument in single quotes', false]),
         OptBool.new('Powershell::no_equals', [true, 'Pad base64 until no "=" remains', false]),
         OptEnum.new('Powershell::method', [true, 'Payload delivery method', 'reflection', %w[net reflection old msil]])
       ]
@@ -223,7 +222,7 @@ def run_hidden_psh(ps_code, payload_arch, encoded)
   # @return [String] Powershell command line with payload
   def cmd_psh_payload(pay, payload_arch, opts = {})
     %i[persist prepend_sleep exec_in_place encode_final_payload encode_inner_payload
-    remove_comspec noninteractive use_single_quotes no_equals method].map do |opt|
+    remove_comspec noninteractive no_equals method].map do |opt|
       opts[opt] ||= datastore["Powershell::#{opt}"]
     end