If you want to try using the functionality provided by Oozie, the script for this is part of the oozie-setup.sh script under the bin dir. You would use one of the following commands:
To create the sharelib:
oozie-setup.sh sharelib create -fs FS_URI [-locallib SHARED_LIBRARY]
where FS_URI is the HDFS URI (i.e. the value of fs.default.name): e.g. hdfs://localhost:8020
and SHARED_LIBRARY is the local path to the sharelib tarball or expanded tarball (i.e. a folder)
To upgrade (i.e. replace) an existing sharelib:
oozie-setup.sh sharelib upgrade -fs FS_URI [-locallib SHARED_LIBRARY]
where the arguments are the same as above.
Either command should be run as the user who will be starting the Oozie server (typically "oozie").
Behind the scenes those two commands are fairly basic, they essentially just upload a directory to HDFS; its not like oozie-setup.sh is doing anything special. So if its easier for Bigtop to do the equivalent in init-hdfs.sh, then feel free to keep doing that.