pgsql: Fix pg_get_functiondef() to print a function's LEAKPROOF propert

Fix pg_get_functiondef() to print a function's LEAKPROOF property.

Seems to have been an oversight in the original leakproofness patch.
Per report and patch from Jeevan Chalke.

In passing, prettify some awkward leakproof-related code in AlterFunction.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/27bae8d964f7eeb61e7e6e57586e7cb9b571b94c

Modified Files
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src/backend/commands/functioncmds.c |    4 ++--
src/backend/utils/adt/ruleutils.c   |    2 ++
2 files changed, 4 insertions(+), 2 deletions(-)