configure: do not check for kill

Introduced by:
commit 3c37a171
    Add check for kill() to fix build of cgroups on win32

Made redundant by:
commit 02f1fd41
    cgroup macros refactoring, part 1
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

configure.ac

@@ -334,7 +334,6 @@ AC_CHECK_FUNCS_ONCE([\
   getrlimit \
   getuid \
   if_indextoname \
-  kill \
   mmap \
   newlocale \
   posix_fallocate \