Fix upgrade message. Closes #644.
Fix upgrade message. Closes #644.

Lw-Cui/vimium,poacher2k/vimium,poacher2k/vimium,elegantwww/vimium,tuchangwei/vimium,willsALMANJ/vimium,PickRelated/vimium,crazypenguincode/vimium,elegantwww/vimium,elderbas/vimium,zhangmin510/vimium,bkudria/vimium,Lw-Cui/vimium,wildeyes/vimium,smblott-github/vimium-smblott,Aleroniponi/vimium,csmalin/vimium,csmalin/vimium,douglas-larocca/vimium,jb55/vimium-plus,philc/vimium,willsALMANJ/vimium,bkudria/vimium,justalittlenoob/vimium,jb55/vimium-plus,PrestanceDesign/vimium,dimatter/vimium,Robinson10240/vimium,wildeyes/vimium,douglas-larocca/vimium,borgified/vimium,poacher2k/vimium,wildeyes/vimium,hhsue/vimium,bkudria/vimium,gdh1995/vimium,Aleroniponi/vimium,borgified/vimium,smblott-github/vimium-smblott,crazypenguincode/vimium,hhsue/vimium,dimatter/vimium,mrmr1993/vimium,borgified/vimium,elderbas/vimium,elderbas/vimium,zhangmin510/vimium,mrmr1993/vimium,PrestanceDesign/vimium,dimatter/vimium,decaffeinate-examples/vimium,philc/vimium,mrmr1993/vimium,VPashkov/vimium,justalittlenoob/vimium,PrestanceDesign/vimium,willsALMANJ/vimium,tuchangwei/vimium,zhangmin510/vimium,Lw-Cui/vimium,decaffeinate-examples/vimium,PickRelated/vimium,csmalin/vimium,smblott-github/vimium,cyrixhero/vimium,elegantwww/vimium,smblott-github/vimium,VPashkov/vimium,cyrixhero/vimium,Aleroniponi/vimium,gdh1995/vimium,VPashkov/vimium,Robinson10240/vimium,Robinson10240/vimium,cyrixhero/vimium,douglas-larocca/vimium,decaffeinate-examples/vimium,PickRelated/vimium,hhsue/vimium,smblott-github/vimium,gdh1995/vimium,philc/vimium,justalittlenoob/vimium,tuchangwei/vimium