fix refefences clobbering
fix refefences clobbering

only update models from references in a patch-doc message when it is
requried, otherwise existing models can get erroneously overwritten

phobson/bokeh,rs2/bokeh,percyfal/bokeh,rs2/bokeh,msarahan/bokeh,philippjfr/bokeh,timsnyder/bokeh,Karel-van-de-Plassche/bokeh,phobson/bokeh,mindriot101/bokeh,percyfal/bokeh,ptitjano/bokeh,quasiben/bokeh,msarahan/bokeh,quasiben/bokeh,schoolie/bokeh,schoolie/bokeh,bokeh/bokeh,DuCorey/bokeh,Karel-van-de-Plassche/bokeh,KasperPRasmussen/bokeh,KasperPRasmussen/bokeh,justacec/bokeh,timsnyder/bokeh,justacec/bokeh,ptitjano/bokeh,dennisobrien/bokeh,clairetang6/bokeh,Karel-van-de-Plassche/bokeh,azjps/bokeh,dennisobrien/bokeh,stonebig/bokeh,jakirkham/bokeh,phobson/bokeh,azjps/bokeh,DuCorey/bokeh,schoolie/bokeh,clairetang6/bokeh,msarahan/bokeh,dennisobrien/bokeh,quasiben/bokeh,KasperPRasmussen/bokeh,philippjfr/bokeh,percyfal/bokeh,DuCorey/bokeh,KasperPRasmussen/bokeh,ericmjl/bokeh,clairetang6/bokeh,rs2/bokeh,Karel-van-de-Plassche/bokeh,timsnyder/bokeh,timsnyder/bokeh,stonebig/bokeh,philippjfr/bokeh,aiguofer/bokeh,dennisobrien/bokeh,ericmjl/bokeh,aavanian/bokeh,aavanian/bokeh,draperjames/bokeh,aavanian/bokeh,draperjames/bokeh,draperjames/bokeh,ericmjl/bokeh,Karel-van-de-Plassche/bokeh,aiguofer/bokeh,justacec/bokeh,aavanian/bokeh,schoolie/bokeh,azjps/bokeh,aiguofer/bokeh,stonebig/bokeh,rs2/bokeh,stonebig/bokeh,justacec/bokeh,ericmjl/bokeh,azjps/bokeh,dennisobrien/bokeh,jakirkham/bokeh,clairetang6/bokeh,DuCorey/bokeh,bokeh/bokeh,percyfal/bokeh,ericmjl/bokeh,schoolie/bokeh,mindriot101/bokeh,msarahan/bokeh,ptitjano/bokeh,mindriot101/bokeh,draperjames/bokeh,bokeh/bokeh,philippjfr/bokeh,bokeh/bokeh,bokeh/bokeh,aiguofer/bokeh,jakirkham/bokeh,philippjfr/bokeh,percyfal/bokeh,aiguofer/bokeh,phobson/bokeh,rs2/bokeh,jakirkham/bokeh,aavanian/bokeh,timsnyder/bokeh,mindriot101/bokeh,KasperPRasmussen/bokeh,jakirkham/bokeh,DuCorey/bokeh,phobson/bokeh,azjps/bokeh,draperjames/bokeh,ptitjano/bokeh,ptitjano/bokeh