@jmk I too had a similar problem. You can look here for my take on this issue.
In a nutshell, I did not find any way to correct this error other than removing each and every file which contains name “mongo”, uninstalling the package and then reinstalling it over again.
NOTE: All this is valid if mongodb ran on your system at least once before it started showing failed (Result: core-dumped)
I’d suggest backing up the data before deleting it.