bugfix - allow use of external skymodel

steps/find_skymodel_target.cwl

@@ -45,19 +45,18 @@ requirements:
 
           SkymodelPath = inputs['SkymodelPath']
           if SkymodelPath is None:
-              SkymodelPath = os.getcwd() + "/target.skymodel"
+              pass
           else:
               SkymodelPath = SkymodelPath["path"]
+              shutil.copyfile(SkymodelPath, "target.skymodel")
 
+          SkymodelPath = os.getcwd() + "/target.skymodel"
           Radius = inputs['Radius']
           Source = inputs['Source']
           DoDownload = str(inputs['DoDownload'])
 
           output = download_skymodel_target(mss, SkymodelPath, Radius, DoDownload, Source)
 
-          if "target.skymodel" not in SkymodelPath:
-             shutil.copyfile(SkymodelPath, "target.skymodel")
-
 outputs:
   - id: skymodel
     type: File?