Please add libsmbclient to seed

[Alan Pope 🍺🐧🐱 🦄]

libsmbclient is required by the file manager app to support connecting to samba shares.
Once added, other applications could of course make use of this library too.

Tested installing on my vivid krillin to roughly gauge what space would be taken up:-

phablet@ubuntu-phablet:~$ sudo apt-get install libsmbclient
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  libldb1 libntdb1 libpython-stdlib libpython2.7 libpython2.7-minimal libpython2.7-stdlib libtalloc2 libtevent0
  libwbclient0 python python-minimal python-talloc python2.7 python2.7-minimal samba-libs
Suggested packages:
  python-doc python-tk python2.7-doc binutils binfmt-support
The following NEW packages will be installed:
  libldb1 libntdb1 libpython-stdlib libpython2.7 libpython2.7-minimal libpython2.7-stdlib libsmbclient libtalloc2
  libtevent0 libwbclient0 python python-minimal python-talloc python2.7 python2.7-minimal samba-libs
0 upgraded, 16 newly installed, 0 to remove and 8 not upgraded.
Need to get 8,424 kB of archives.
After this operation, 31.0 MB of additional disk space will be used.
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