pgsql: Fix pg_rewind regression tests in VPATH builds

Fix pg_rewind regression tests in VPATH builds

Should call just "pg_rewind", instead of "./pg_rewind". The tests are called
so that PATH contains the temporariy installation bin dir.

Per report from Alvaro Herrera

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b22a36a62ce312c1df9477382d1da602b0c24f6f

Modified Files
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src/bin/pg_rewind/RewindTest.pm |    4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)