pgsql: Make wal streaming the default mode for pg_basebackup

Make wal streaming the default mode for pg_basebackup

Since streaming is now supported for all output formats, make this the
default as this is what most people want.

To get the old behavior, the parameter -X none can be specified to turn
it off.

This also removes the parameter -x for fetch, now requiring -X fetch to
be specified to use that.

Reviewed by Vladimir Rusinov, Michael Paquier and Simon Riggs

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/9a4d51077c96c10322582211781bb969b51822ff

Modified Files
--------------
doc/src/sgml/ref/pg_basebackup.sgml | 42 ++++++++++++------------
src/bin/pg_basebackup/pg_basebackup.c | 49 ++++++++++++----------------
src/bin/pg_basebackup/t/010_pg_basebackup.pl | 9 +++--
src/test/perl/PostgresNode.pm | 2 +-
4 files changed, 50 insertions(+), 52 deletions(-)