pgsql: Simplify static function in extension.c

Simplify static function in extension.c

An extra argument for the filename defining the extension script
location was present, aimed at being used for error reporting, but has
never been used.  This was around since extensions have been added in
d9572c4.

Author: Yugo Nagata
Reviewed-by: Tatsuo Ishii
Discussion: https://postgr.es/m/20180907180504.1ff19e1675bb44a67e9c7ab1@sraoss.co.jp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/514a731ddcd8449d8a7bfb96f138c72c694a7ef8

Modified Files
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src/backend/commands/extension.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)