VariableIsUndefined error when not renaming host

VariableIsUndefined error when not renaming host thanks to PowerShell
strict mode. Resolved by using boolean to check if rename operation
needs to be performed.

Author: MattHodge

Functions/ConvertTo-GraphiteMetric.ps1

@@ -56,6 +56,9 @@ Function ConvertTo-GraphiteMetric
         [System.Collections.Specialized.OrderedDictionary]$MetricReplacementHash
     )
 
+    # Setup booleen for if we are changing hostname
+    $renameHost = $false
+
     # If HostName is being overwritten
     if ($HostName -ne $env:COMPUTERNAME)
     {
@@ -64,6 +67,9 @@ Function ConvertTo-GraphiteMetric
 
         # Set the host name to the hostGuid
         $MetricToClean = $MetricToClean -replace "\\\\$($env:COMPUTERNAME)\\","\\$($hostGuid)\"
+
+        $renameHost = $true
+        
     }
 
     if ($MetricReplacementHash -ne $null)
@@ -152,11 +158,12 @@ Function ConvertTo-GraphiteMetric
     }
 
     # If $hostGuid has been generated, replace the guid inside the metrics with the correct HostName
-    if ($hostGuid)
+    if ($renameHost)
     {
         Write-Verbose "Replacing hostGuid '$($hostGuid)' with requested Hostname '$($HostName)'"
         $cleanNameOfSample = $cleanNameOfSample -replace $hostGuid,$HostName
     }
 
+
     Write-Output $cleanNameOfSample
 }