$meta['quote_source_name'] in get_the_post_format_quote() needs to be escaped

[tollmanz]

HTML in $meta['quote_source_name'] should be escaped when accessed via get_the_post_format_quote(). Adding certain HTML to the source name can break the layout.

For instance:

This can be recreated by doing the following:

1. Add a new quote post
2. Give it a title and some text
3. In the "Quote Source" field, add </div>

[tollmanz]

​24418.patch escapes the data with esc_html().

[ocean90]

[24399] / #24452