utimensat: do not reference an out-of-scope buffer

utimensat: do not reference an out-of-scope buffer

Otherwise, with __linux__ defined, "times" would point to a buffer, "ts"
declared in an inner scope, yet "times" would be dereferenced outside
the scope in which "ts" was valid.
* lib/utimensat.c (rpl_utimensat) [__linux__]: Move the declaration
of ts[2] "out/up", so that the use of aliased "times" (via "times = ts;")
does not end up referencing an out-of-scope "ts"