pgsql: Remove scandir() requirement in pg_upgrade; instead just use re

Remove scandir() requirement in pg_upgrade;  instead just use readdir()
--- we were not using the scandir pattern filtering anyway.  This also
removes the scandir requirement in configure.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/7012b5edb7f12be9f9d2816bb64fcb80515cc18c

Modified Files
--------------
configure | 3 +-
configure.in | 2 +-
contrib/pg_upgrade/file.c | 96 +++++++++-----------------------------
contrib/pg_upgrade/pg_upgrade.h | 3 +-
contrib/pg_upgrade/relfilenode.c | 2 +-
5 files changed, 26 insertions(+), 80 deletions(-)