fix bug when a citeproc error occurs in a style with non bibliography
fix bug when a citeproc error occurs in a style with non bibliography

citation-style-language/csl-editor,adam3smith/csl-editor,citation-style-language/csl-editor,citation-style-language/csl-editor,adam3smith/csl-editor,fbennett/csl-editor,fbennett/csl-editor,citation-style-editor/csl-editor,adam3smith/csl-editor,citation-style-editor/csl-editor,citation-style-editor/csl-editor