Updated _flashes.html.erb with proper id
Updated _flashes.html.erb with proper id

In Bitters' generated `flash.scss`,
the selectors use "-" instead of "_".

http://refills.bourbon.io/components/#flashes

nilbus/suspenders,wizarddevelopment/bowties,Mario245/suspenders,LiveTyping/suspenders,askl56/suspenders,pedrosmmoreira/suspenders,LiveTyping/suspenders,headwayio/voyage,mukkoo/welaika-suspenders,nplusp/suspenders,pacso/suspenders,mico/suspenders,nilbus/suspenders,thoughtbot/suspenders,pedrosmmoreira/suspenders,askl56/suspenders,wizarddevelopment/bowties,elevatorup/eu-suspenders,askl56/suspenders,headwayio/suspenders,thoughtbot/suspenders,toobulkeh/suspenders,LiveTyping/suspenders,headwayio/suspenders,Mossio/hashira-rails,elevatorup/eu-suspenders,namuit/welaika-suspenders,welaika/welaika-suspenders,kvokka/suspenders,namuit/welaika-suspenders,pineapplethief/suspenders,headwayio/suspenders,mib32/suspenders,wizarddevelopment/bowties,delphaber/suspenders,welaika/welaika-suspenders,zamith/suspenders,namuit/welaika-suspenders,headwayio/voyage,lorentrogers/suspenders,adarsh/suspenders,nplusp/suspenders,nplusp/suspenders,mib32/suspenders,mib32/suspenders,philosophie/suspenders,pacso/suspenders,cybrilla/suspenders,mukkoo/welaika-suspenders,brandoncordell/suspenders,pineapplethief/suspenders,delphaber/suspenders,netflower/netflower-suspenders,kvokka/suspenders,Mario245/suspenders,adarsh/suspenders,cybrilla/suspenders,cybrilla/suspenders,thoughtbot/suspenders,adarsh/suspenders,toobulkeh/suspenders,elevatorup/eu-suspenders,Mario245/suspenders,elijahkim/suspenders,nilbus/suspenders,mico/suspenders,reshleman/suspenders,Mossio/hashira-rails,headwayio/voyage,pedrosmmoreira/suspenders,welaika/welaika-suspenders,mukkoo/welaika-suspenders,reshleman/suspenders,Mossio/hashira-rails,elijahkim/suspenders,mico/suspenders,philosophie/suspenders,elijahkim/suspenders,lorentrogers/suspenders,toobulkeh/suspenders,InnovativeOperations/suspenders,LiveTyping/suspenders,pacso/suspenders,Mossio/hashira-rails,InnovativeOperations/suspenders,zamith/suspenders,headwayio/suspenders,kvokka/suspenders,netflower/netflower-suspenders,brandoncordell/suspenders,headwayio/voyage,InnovativeOperations/suspenders,zamith/suspenders,brandoncordell/suspenders,pineapplethief/suspenders,delphaber/suspenders,philosophie/suspenders,reshleman/suspenders,lorentrogers/suspenders