pgsql: Fix handling of symlinked pg_stat_tmp and pg_replslot

pgsql: Fix handling of symlinked pg_stat_tmp and pg_replslot

Fix handling of symlinked pg_stat_tmp and pg_replslot

This was already fixed in HEAD as part of 6ad8ac60 but was not
backpatched.

Also change the way pg_xlog is handled to be the same as the other
directories.

Patch from me with pg_xlog addition from Michael Paquier, test updates
from David Steele.

Branch
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REL9_5_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/6d779e05a03d2c06433b71b76f9b0168d47d1a3e

Modified Files
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src/backend/replication/basebackup.c | 48 ++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 18 deletions(-)