LU-4655 libcfs: properly (un)define CDEBUG_ENTRY_EXIT

LU-4655 libcfs: properly (un)define CDEBUG_ENTRY_EXIT

In lustre-libcfs.m4 we defined CDEBUG_ENTRY_EXIT to 1 or 0 according
to whether libcfs-trace was enabled. But in libcfs_debug.h we tested
CDEBUG_ENTRY_EXIT using #ifdef and enabled the trace macros
accrodingly. Fix this and use CDEBUG_ENTRY_EXIT to control GOTO()
tracing as well. The ability to properly disable these macros will
make some static analyses easier.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ia016b4ddd45f8c39704a84908665757aa17bd3d2
Reviewed-on: http://review.whamcloud.com/9517
Tested-by: Jenkins
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>