make check: Fix when running with lsmenv.
make check: Fix when running with lsmenv.

* lsmenv will create link in python_binding/lsm folder to plugin and lsmcli
  which cannot detected by bash [ -e $FILE_PATH], fixed by checking 'test -L'
  also.

Signed-off-by: Gris Ge <e24f3acbe39bf94f92e8af3c48f8852106ad5ad7@redhat.com>

HP-Scale-out-Storage/libstoragemgmt,joehandzik/libstoragemgmt,cathay4t/libstoragemgmt,libstorage/libstoragemgmt,cathay4t/libstoragemgmt,jumitche/libstoragemgmt,cathay4t/libstoragemgmt,libstorage/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,jumitche/libstoragemgmt,jumitche/libstoragemgmt,joehandzik/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,libstorage/libstoragemgmt,jumitche/libstoragemgmt,joehandzik/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,tasleson/libstoragemgmt,tasleson/libstoragemgmt,cathay4t/libstoragemgmt,tasleson/libstoragemgmt,cathay4t/libstoragemgmt,joehandzik/libstoragemgmt,libstorage/libstoragemgmt,jumitche/libstoragemgmt,tasleson/libstoragemgmt