pgsql: pg_upgrade: properly handle timeline variables

pg_upgrade:  properly handle timeline variables

There is no behavior change here as we now always set the timeline to
one.

Report by Tom Lane

Backpatch to 9.3 and 9.4

Branch
------
REL9_4_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/5f65396359e9e44c8f5eb5133cb50abba6326bb6

Modified Files
--------------
contrib/pg_upgrade/controldata.c |   10 +++-------
contrib/pg_upgrade/pg_upgrade.h  |    1 -
2 files changed, 3 insertions(+), 8 deletions(-)