Fixed backtrace in error reports

app/views/user_mailer/error_report.html.haml

@@ -1,9 +1,8 @@
 %h1=@title
 
 %h2 Error details
-%code.signature{class: "#{@report.source}-signature"}
+%code.signature{class: "#{@report.source}-signature"}=@report.signature
-  = "#{@report.signature.gsub(/\n\s+/, '<br>&nbsp;nbsp;')}".html_safe
+%code.backtrace{class: "#{@report.source}-backtrace"}=@report.backtrace.gsub(/\n\s+/, '<br>&nbsp;nbsp;').html_safe
-%code.backtrace{class: "#{@report.source}-backtrace"}=@report.backtrace
 
 %h2 Request details
 .request-details