handle broken layer files (e.g. ArcMap version mismatch).
handle broken layer files (e.g. ArcMap version mismatch).

~~~
Areas - by Taxonomic Group\WKA Woodland Caribou Level 3 - 250k.lyr
Failed script save-layers-my-credentials...

Traceback (most recent call last):
  File {snipped}...Dev\Tools\Scripts\save-layers-my-credentials.py", line 111, in <module>
    lyr = arcpy.mapping.Layer(L)
  File "c:\program files (x86)\arcgis\desktop10.4\arcpy\arcpy\arcobjects\mixins.py", line 402, in __init__
    super(LayerMixin, self).__init__(lyrfile)
  File "c:\program files (x86)\arcgis\desktop10.4\arcpy\arcpy\arcobjects\_base.py", line 47, in __init__
    for arg in args))
ValueError: Object: CreateObject Layer invalid data source

Failed to execute (save-layers-my-credentials).
Failed at Thu Sep 26 09:45:29 2019 (Elapsed Time: 2 minutes 56 seconds)
~~~

maphew/arcplus,maphew/arcplus