This reverts commit 327d364f34.
Reverted due to the problem with reload signal sent by systemd.
`frostfs-ir` service reconfigures correctly and service's
statuses are being reported to systemd. However, since we
replaced `go:linkname` & `nanotime()` with `time.Since()`,
systemd refuses to accept reload signal response from
`frostfs-ir`. To maintain correct behaviour it was decided to
revevrt systemd-related changes until a better solution is
found.
Signed-off-by: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>
