cscope: ignore symbolic linked files

When it is run, cscope complains about files it cannot find:

cscope: cannot find file test/zdtm/live/streaming/socket-tcp.c
cscope: cannot find file test/zdtm/live/streaming/socket-tcp6.c
cscope: cannot find file test/zdtm/live/static/socket-tcpbuf-local.c
cscope: cannot find file test/zdtm/live/static/mntns_shared_bind02.c
cscope: cannot find file test/zdtm/live/static/socket_listen6.c
cscope: cannot find file test/zdtm/live/static/socket-tcp6.c
cscope: cannot find file test/zdtm/live/static/socket-tcpbuf6.c
cscope: cannot find file test/zdtm/live/static/mntns_link_ghost.c
cscope: cannot find file test/zdtm/live/transition/fork2.c

These files are relative symbolic links, and since cscope is run at the top
directory, the ../* links are not valid.

This patch removes the symbolic links from the list of scanned files. This
is not removing any tags since the real file are still scanned.

In addition, the test directory is not taken in account.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>