Adds possibility to change another user password

[github at samba.org]

New comment by abartlet on Samba Github repository

https://github.com/samba-team/samba/pull/42#issuecomment-162075755
Comment:
Thanks.  This (and samba-technical) is where we discuss patches, so you have indeed done the right thing.

In terms of the actual patch, can you investigate if the same kind of modification could be made to samba-tool or net instead? smbpasswd is essentially frozen in time at this point, new functionality is added to our more general (and esaiser to expand) tools.

In particular, this is because smbpasswd has enough of a non-standard command-line syntax as it is (inconsistent with the rest of samba, and getopt rather than popt based).

Sorry,

Andrew Bartlett