Fix tests for pt-archiver

$ prove -vw --trap --timer t/pt-archiver/
...
[17:19:11] t/pt-archiver/pt-1898.t ................. 
1..6
# Setting slave delay to 0 seconds
# Loading test data
Failed to execute /home/sveta/src/percona-toolkit/t/pt-online-schema-change/samples/pt-1898.sql on master: ERROR 1064 (42000) at line 7: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.
USE test' at line 1
unlink0: /tmp/SlnkrYUzVm is gone already at /home/sveta/src/percona-toolkit/lib/Sandbox.pm line 171.
# Looks like your test exited with 1 before it could output anything.
Dubious, test returned 1 (wstat 256, 0x100)
Failed 6/6 subtests 
...
[17:20:43] t/pt-archiver/standard_options.t ........ 
ok 1 - DSNs inherit from standard connection options (issue 248)
ok 2 - Exits because of sentinel
ok 3 - No rows were deleted
ok 4 - Created the sentinel OK
not ok 5 - Dies if PID file already exists (issue 391)

#   Failed test 'Dies if PID file already exists (issue 391)'
#   at t/pt-archiver/standard_options.t line 102.
#                   'Can't locate object method "make_PID_file" via package "Daemon" at /home/sveta/src/percona-toolkit/bin/pt-archiver line 6233.
# '
#     doesn't match '(?^:PID file /tmp/pt-archiver-test.pid.89657 already exists)'
ok 6 - --dest inherited from --source
ok 7 - Sandbox servers
1..7
# Looks like you failed 1 test of 7.
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/7 subtests 
[17:20:46]

Test Summary Report
-------------------
t/pt-archiver/pt-1898.t               (Wstat: 256 Tests: 0 Failed: 0)
  Non-zero exit status: 1
  Parse errors: Bad plan.  You planned 6 tests but ran 0.
t/pt-archiver/standard_options.t      (Wstat: 256 Tests: 7 Failed: 1)
  Failed test:  5
  Non-zero exit status: 1
Files=29, Tests=212, 297 wallclock secs ( 0.15 usr  0.04 sys + 26.30 cusr 10.98 csys = 37.47 CPU)
Result: FAIL

Test Summary Report
-------------------
t/pt-archiver/bulk_insert.t           (Wstat: 24320 Tests: 10 Failed: 1)
  Failed test:  10
  Non-zero exit status: 95
  Parse errors: No plan found in TAP output
t/pt-archiver/issue_1225.t            (Wstat: 512 Tests: 5 Failed: 2)
  Failed tests:  3-4
  Non-zero exit status: 2
t/pt-archiver/issue_1229.t            (Wstat: 512 Tests: 1 Failed: 0)
  Non-zero exit status: 2
  Parse errors: No plan found in TAP output
t/pt-archiver/pt-1898.t               (Wstat: 256 Tests: 0 Failed: 0)
  Non-zero exit status: 1
  Parse errors: Bad plan.  You planned 6 tests but ran 0.
Files=29, Tests=202, 299 wallclock secs ( 0.11 usr  0.03 sys + 23.73 cusr  8.43 csys = 32.30 CPU)
Result: FAIL