Replacing whoami with id -un to be more POSIX.2 compliant [JIRA: TOOLS-143]

[drewkerrigan]

Per the suggestion in the comments from #185, replacing the questionably supported whoami with id -un for collecting the current user for execution scripts.

Reference: http://pubs.opengroup.org/onlinepubs/007908799/xcu/id.html

[DSomogyi]

create jira issue

[Basho-JIRA]

merged [done]

_[posted via JIRA by David Andersen]_

[jaredmorrow]

There was a reason id -un wasn't used and it was due to the continuing support of Solaris 10. Solaris 10 does not have -u as an option in /usr/bin/id.

# id -un
id: illegal option -- u
Usage: id [-ap] [user]

There are some weird things in node_package that don't seem to make any sense, but most of them are due to the original support of Solaris 10 and it's billion-year-old userland.

You can fix this by going back to whoami which I tested originally and is supported on all the destination OS's Riak supports. Or you can add /usr/xpg4/bin to the head of the path in the solaris package only. The problem with that is you'll now get all new EVERYTHING so you'll have to test it on Solaris 10, which is as fun as it sounds.