pgsql: Remove some code related to 7.3 and older servers from toolsof

Remove some code related to 7.3 and older servers from tools of src/bin/

This code was broken as of 582edc3, and is most likely not used anymore.
Note that pg_dump supports servers down to 8.0, and psql has code to
support servers down to 7.4.

Author: Julien Rouhaud
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/CAOBaU_Y5y=zo3+2gf+2NJC1pvMYPcbRXoQaPXx=U7+C8Qh4CzQ@mail.gmail.com

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/6bd3203b9e54a39805b531c3ce7e44e444c98541

Modified Files
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src/bin/scripts/common.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)