pgsql: pg_upgrade; change major version comparisons to use <=, not <

pg_upgrade; change major version comparisons to use <=, not <

This makes checking for older major versions more consistent.

Backpatch-through: 9.5

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/f09e2a8c6307058aa767924516bb057cc9cedef8

Modified Files
--------------
src/bin/pg_upgrade/check.c | 6 +++---
src/bin/pg_upgrade/controldata.c | 2 +-
src/bin/pg_upgrade/exec.c | 6 +++---
src/bin/pg_upgrade/function.c | 4 ++--
src/bin/pg_upgrade/pg_upgrade.c | 6 +++---
src/bin/pg_upgrade/server.c | 2 +-
6 files changed, 13 insertions(+), 13 deletions(-)