Rewrite CitationCache code to use EPrints API rather than SQL query

[drn05r]

The following line was original written as SQL for expediency and should have be modified to use the EPrints API once the correct query was determined.

eprints3.4/perl_lib/EPrints/DataObj.pm

Line 1576 in 5d549e5

my $citations_sql = "SELECT `citationcacheid`, `citation_text`, `timestamp_year` AS `year`, `timestamp_month` AS `month`, `timestamp_day` AS `day`, `timestamp_hour` AS `hour`, `timestamp_minute` AS `minute`, `timestamp_second` AS `second` FROM `citationcache` WHERE `datasetid` = '" . $self->{dataset}->confid . "' AND `objectid` = '" . $self->id . "' AND `style` = '" . $style . "' ORDER BY `timestamp_year`, `timestamp_month`, `timestamp_day`, `timestamp_hour`, `timestamp_minute`, `timestamp_second` DESC LIMIT 1";

[drn05r]

Also fix EPrints::DataObj::clear_citationcaches function to use EPrints API.