When running postgres from nix-shell, nix creates a directory
structure like `postgrest/postgrest-with-pg-17-XXX` in the `/tmp`
directory. This commit removes the extra `postgrest/` prefix to
shorten length of absolute path length of filenames.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
(cherry picked from commit 802cce9a28)