Rename -L to -U and deprecate -L usage
The -L flag is being renamed elsewhere
search/rquery: Automatically update repo catalogue

The -U flag and REPO_AUTOUPDATE are available to disable this.

Issue:	#424
rquery/search: Be quiet when updating as the output is being used in scripts

The alternative is to send the output to stderr but I think that would be harder
to maintain and be error prone. If something is added and we forget to stderr it
in this call chain then scripts may end up parsing it

Issue:	#424