bug 2459: fix module depedency error blocking SIP2

bug 2459: fix module depedency error blocking SIP2

Ror a poorly understood (by me) reason, use of 'use
UNIVERSAL' and 'use C4::Auth' in the SIP2 code is resulting
in a compilation error, thus blocking SIP2 from working.

The error (prior to this patch) could be reproduced as follows:

cd C4/SIP
perl -I. -wc Sip/MsgType.pm
"get_session" is not exported by the C4::Auth module
Can't continue after import errors at /home/gmc/koha/dev/C4/VirtualShelves.pm
line 51
BEGIN failed--compilation aborted at /home/gmc/koha/dev/C4/VirtualShelves.pm
line 51.
Compilation failed in require at /home/gmc/koha/dev/C4/Auth.pm line 34.
BEGIN failed--compilation aborted at /home/gmc/koha/dev/C4/Auth.pm line 34.
Compilation failed in require at Sip/MsgType.pm line 21.
BEGIN failed--compilation aborted at Sip/MsgType.pm line 21.

or more minimally

perl -ce 'use UNIVERSAL; use C4::Auth;'

This patch works around the problem by making C4::Auth
and C4::VirtualShelves not import any symbols
from each other.

Signed-off-by: Joshua Ferraro <jmf@liblime.com>