pgsql: Get rid of useless global variable in pg_upgrade.

Get rid of useless global variable in pg_upgrade.

Since the scandir() emulation was taken out of pg_upgrade, there's
no longer any need for scandir_file_pattern to exist as a global
variable. Replace it with a local in the one remaining function
that was making use of it.

Branch
------
REL9_2_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/ebd9e26daa3df6518e3d403ef94a86e33168eae3

Modified Files
--------------
contrib/pg_upgrade/pg_upgrade.h | 1 -
contrib/pg_upgrade/relfilenode.c | 19 +++++++++----------
2 files changed, 9 insertions(+), 11 deletions(-)