Fixes Bug 1040365 - added dump name mangling & test

for historical reasons probably caused by a bug in the past, the default minidump can be referred to with the name "dump" or "upload_file_minidump".  The  Ceph crashstore module did not take that into account.  

This PR duplicates the code in the HBase crashstore that does the name mangling so the dump is saved/fetched properly