(PA-7407) Add more detailed error information when upgrade fails

This commit outputs information on any error(s) that caused the
puppet-agent upgrade on Windows to fail. Previously, when the
upgrade fails with a ScriptHalted error, only the error is
provided with no other information on why it failed.

This commit updates install_puppet.ps1 to put any errors
from installer.log into puppet_agent_upgrade_failure.log.
Then, in the puppet_agent_upgrade_error, read_content_and_delete_file()
will output the error information from the error log then delete
the error log.

Author: AriaXLi

files/install_puppet.ps1

@@ -347,6 +347,9 @@ try {
     Reset-PuppetresDLL $temp_puppetres
   }
   "$_" | Out-File -FilePath (Join-Path -Path $state_dir -ChildPath 'puppet_agent_upgrade_failure.log')
+  # Put relevant errors in puppet_agent_upgrade_failure.log
+  Get-Content -Path $logfile | Select-String -Pattern "^Error.*$|-- Error" | Add-Content -Path (Join-Path -Path $state_dir -ChildPath 'puppet_agent_upgrade_failure.log')
+  Get-Content -Path $Logfile -Tail 10 | Add-Content -Path (Join-Path -Path $state_dir -ChildPath 'puppet_agent_upgrade_failure.log')
 } finally {
   Reset-PuppetServices $services_before
   Unlock-Installation $install_pid_lock

lib/puppet/provider/puppet_agent_upgrade_error/puppet_agent_upgrade_error.rb

@@ -19,7 +19,7 @@ def read_content_and_delete_file(filename)
                 # In this scenario we need to open the file in binmode and read each line
                 # individually, then encode the result back to UTF-8 so we can sub out both
                 # the UTF-16 header \uFEFF and the \r\n line carriages.
-                File.open(logfile, 'rb:UTF-16LE') { |file| file.readlines }[0].encode!('UTF-8').delete("\uFEFF").delete("\r")
+                File.open(logfile, 'rb:UTF-16LE') { |file| file.read.encode!('UTF-8').delete("\uFEFF").delete("\r") }
               else
                 File.read(logfile)
               end