Output the log path when mongod/mongos launch fails

[p-mongo]

When mlaunch fails to spawn mongod or mongos, it tries to output a log excerpt. This exceprt can be useless in some situations, e.g.:

launching: config server on port 16046                                                                                 
b'{"t":{"$date":"2022-06-23T00:01:17.482Z"},"s":"I",  "c":"CONTROL",  "id":5760901, "ctx":"-","msg":"Applied --setParam
eter options","attr":{"serverParameters":{"enableTestCommands":{"default":false,"value":true}}}}\nabout to fork child p
rocess, waiting until server is ready for connections.\nforked process: 6585\nERROR: child process failed, exited with 
48\nTo see additional information in this output, start without the "--fork" option.\n'                                

can't start process, return code 48. tried to launch: "/usr/local/m/versions/6.0/mongod" --replSet shard01 --dbpath "/m
nt/zram/mongodb/6.0-scm/shard01/rs1/db" --logpath "/mnt/zram/mongodb/6.0-scm/shard01/rs1/mongod.log" --port 16042 --for
k  --setParameter "enableTestCommands=1" --filePermissions "0666" --shardsvr --wiredTigerCacheSizeGB 1        

To assist in troubleshooting, print the path to the logfile also.

[stennie]

Thanks @p-mongo !