pgsql: Dept of second thoughts: improve the API for AnalyzeForeignTable

Dept of second thoughts: improve the API for AnalyzeForeignTable.

If we make the initially-called function return the table physical-size
estimate, acquire_inherited_sample_rows will be able to use that to
allocate numbers of samples among child tables, when the day comes that
we want to support foreign tables in inheritance trees.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/cea49fe82fedcf125eb99a780099eaf47a326b03

Modified Files
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contrib/file_fdw/file_fdw.c | 69 +++++++++++++++++------------
doc/src/sgml/fdwhandler.sgml | 28 ++++++------
src/backend/commands/analyze.c | 94 ++++++++++++++++++----------------------
src/include/foreign/fdwapi.h | 8 ++--
4 files changed, 101 insertions(+), 98 deletions(-)