Make helper functions more robust against undefined powershell objects

lib/ansible/module_utils/powershell.ps1

@@ -46,6 +46,12 @@ Function Parse-Args($arguments)
 # Example: Set-Attr $result "changed" $true
 Function Set-Attr($obj, $name, $value)
 {
+    # If the provided $obj is undefined, define one to be nice
+    If (-not $obj.GetType)
+    {
+        $obj = New-Object psobject
+    }
+
     $obj | Add-Member -Force -MemberType NoteProperty -Name $name -Value $value
 }
 
@@ -55,6 +61,8 @@ Function Set-Attr($obj, $name, $value)
 # Example: $attr = Get-Attr $response "code" -default "1"
 Function Get-Attr($obj, $name, $default = $null)
 {
+    # Check if the provided Member $name exists in $obj and return it or the
+    # default
     If ($obj.$name.GetType)
     {
         $obj.$name
@@ -71,6 +79,12 @@ Function Get-Attr($obj, $name, $default = $null)
 # Example: Exit-Json $result
 Function Exit-Json($obj)
 {
+    # If the provided $obj is undefined, define one to be nice
+    If (-not $obj.GetType)
+    {
+        $obj = New-Object psobject
+    }
+
     echo $obj | ConvertTo-Json
     Exit
 }
@@ -78,8 +92,21 @@ Function Exit-Json($obj)
 # Helper function to add the "msg" property and "failed" property, convert the
 # powershell object to JSON and echo it, exiting the script
 # Example: Fail-Json $result "This is the failure message"
-Function Fail-Json($obj, $message)
+Function Fail-Json($obj, $message = $null)
 {
+    # If we weren't given 2 args, and the only arg was a string, create a new
+    # psobject and use the arg as the failure message
+    If ($message -eq $null -and $obj.GetType().Name -eq "String")
+    {
+        $message = $obj
+        $obj = New-Object psobject
+    }
+    # If the first args is undefined or not an object, make it an object
+    ElseIf (-not $obj.GetType -or $obj.GetType().Name -ne "PSCustomObject")
+    {
+        $obj = New-Object psobject
+    }
+
     Set-Attr $obj "msg" $message
     Set-Attr $obj "failed" $true
     echo $obj | ConvertTo-Json