pgsql: Revert "Allow units to be specified in relation option setting v

Revert "Allow units to be specified in relation option setting value."

This reverts commit e23014f3d40f7d2c23bc97207fd28efbe5ba102b.

As the side effect of the reverted commit, when the unit is
specified, the reloption was stored in the catalog with the unit.
This broke pg_dump (specifically, it prevented pg_dump from
outputting restorable backup regarding the reloption) and
turned the buildfarm red. Revert the commit until the fixed
version is ready.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/9df492664a74a948c87232f523eea637920a516b

Modified Files
--------------
src/backend/access/common/reloptions.c | 40 +++++++++++++----------------
src/include/access/reloptions.h | 3 +--
src/test/regress/expected/alter_table.out | 14 ----------
src/test/regress/sql/alter_table.sql | 6 -----
4 files changed, 19 insertions(+), 44 deletions(-)