Removed unnecessary escape sequence

This commit also contains changes to match requests that are 100% empty (by using "*" instead of "+" in the regex)

config/filter.d/nginx-bad-request.conf

@@ -4,7 +4,8 @@
 [Definition]
 
 # The request often doesn't contain a method, only some encoded garbage
-failregex = ^<HOST> \- \S+ \[\] \"[^\"]+\" 400
+# This will also match requests that are entirely empty
+failregex = ^<HOST> - \S+ \[\] "[^"]*" 400
 
 datepattern = {^LN-BEG}%%ExY(?P<_sep>[-/.])%%m(?P=_sep)%%d[T ]%%H:%%M:%%S(?:[.,]%%f)?(?:\s*%%z)?
               ^[^\[]*\[({DATE})