(GH-1781) fix: use ProviderPath for Get-Location

When seeing the following error:
`ERROR: Exception calling "Start" with "0" argument(s): "The directory
name is invalid"` this can stem off of permissions issues or an
incorrectly formatted directory being passed. When using Get-Location,
if that location is a UNC path, PowerShell shows that with
`Microsoft.PowerShell.Core\FileSystem::\\server\share`, resulting in
that entire string to be passed as the PATH for the working directory
that is passed to
`System.Diagnostics.Process.StartInfo.WorkingDirectory`. Unfortunately
that doesn't evaluate to an acutal valid path, thus the error is
produced. Instead, the path should be evaluated with ProviderPath,
which removes the `Microsoft.PowerShell.Core\FileSystem::` from the
actual path, resulting in a valid path using a UNC location.

Also make a determination if the path is not set (such as with things
that are run during provisioning) and provide a valid working directory
using cache location.

src/chocolatey.resources/helpers/functions/Get-ChocolateyUnzip.ps1

@@ -148,7 +148,13 @@ param(
     $destinationNoRedirection = $destination
   }
 
-  $workingDirectory = Get-Location -PSProvider "FileSystem"
+  $workingDirectory = $(Get-Location -PSProvider 'FileSystem')
+  if ($workingDirectory -eq $null -or $workingDirectory.ProviderPath -eq $null) {
+    Write-Debug "Unable to use current location for Working Directory. Using Cache Location instead."
+    $workingDirectory = $env:TEMP
+  }
+  $workingDirectory = $workingDirectory.ProviderPath
+
   $params = "x -aoa -bd -bb1 -o`"$destinationNoRedirection`" -y `"$fileFullPathNoRedirection`""
   if ($specificfolder) {
     $params += " `"$specificfolder`""

src/chocolatey.resources/helpers/functions/Start-ChocolateyProcessAsAdmin.ps1

@@ -65,7 +65,8 @@ Array of exit codes indicating success. Defaults to `@(0)`.
 
 .PARAMETER WorkingDirectory
 The working directory for the running process. Defaults to
-`Get-Location`.
+`Get-Location`. If current location is a UNC path, uses
+`$env:TEMP` for default as of 0.10.14.
 
 Available in 0.10.1+.
 
@@ -117,14 +118,20 @@ param(
   [parameter(Mandatory=$false)][switch] $minimized,
   [parameter(Mandatory=$false)][switch] $noSleep,
   [parameter(Mandatory=$false)] $validExitCodes = @(0),
-  [parameter(Mandatory=$false)][string] $workingDirectory = $(Get-Location -PSProvider "FileSystem"),
+  [parameter(Mandatory=$false)][string] $workingDirectory = $(Get-Location -PSProvider 'FileSystem'),
   [parameter(Mandatory=$false)][string] $sensitiveStatements = '',
   [parameter(ValueFromRemainingArguments = $true)][Object[]] $ignoredArguments
 )
   [string]$statements = $statements -join ' '
 
   Write-FunctionCallLogMessage -Invocation $MyInvocation -Parameters $PSBoundParameters
 
+  if ($workingDirectory -eq $null -or $workingDirectory.ProviderPath -eq $null) {
+    Write-Debug "Unable to use current location for Working Directory. Using Cache Location instead."
+    $workingDirectory = $env:TEMP
+  }
+  $workingDirectory = $workingDirectory.ProviderPath
+
   $alreadyElevated = $false
   if (Test-ProcessAdminRights) {
     $alreadyElevated = $true