Bug 21990: Replace dialog .error with .alert

<div class="dialog error"> will display a div without background color, the correct class is "dialog alert".

https://wiki.koha-community.org/wiki/Interface_patterns#Error_messages

Test plan:
Hit /cgi-bin/koha/acqui/parcel.pl
Notice the background color change with and without this patch

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

koha-tmpl/intranet-tmpl/prog/en/modules/acqui/parcel.tt

@@ -64,7 +64,7 @@
     [% END %]
 
     [% IF (error_cancelling_receipt) %]
-      <div class="dialog error">
+      <div class="dialog alert">
       Cannot cancel receipt. Possible reasons :
       <ul>
         <li>
@@ -82,7 +82,7 @@
     [% END %]
 
     [% IF error_invoice_not_known %]
-        <div class="dialog error">
+        <div class="dialog alert">
             The invoice referenced by this invoiceid does not exist.
         </div>
     [% END %]

koha-tmpl/intranet-tmpl/prog/en/modules/tools/batch_delete_records.tt

@@ -30,7 +30,7 @@
     [% ELSIF message.type == 'warning' %]
       <div class="dialog alert">
     [% ELSIF message.type == 'error' %]
-      <div class="dialog error" style="margin:auto;">
+      <div class="dialog alert" style="margin:auto;">
     [% END %]
     [% IF message.code == 'biblio_not_exists' %]
       The biblionumber [% message.biblionumber | html %] does not exist in the database.