- Fix QUOTEDSTRING pattern (LOGSTASH-446)

  In some cases, Onigiruma gets confused about negative matches, so
  previously a pattern of '%{QS} something', if false match, would
  cause Oniguruma to loop frantickly. I haven't yet dug into
  the part of Oni that does this, but it's common that some regexp
  engines have this behavior. Easy fix moving to non-backtracking
  matches..

patterns/grok-patterns

@@ -12,8 +12,7 @@ NOTSPACE \S+
 SPACE \s*
 DATA .*?
 GREEDYDATA .*
-#QUOTEDSTRING (?:(?<!\\)(?:"(?:\\.|[^\\"])*"|(?:'(?:\\.|[^\\'])*')|(?:`(?:\\.|[^\\`])*`)))
-QUOTEDSTRING (?:(?<!\\)(?:"(?:\\.|[^\\"]+)*"|(?:'(?:\\.|[^\\']+)*')|(?:`(?:\\.|[^\\`]+)*`)))
+QUOTEDSTRING (?:(?<!\\)(?:"(?>[^\\"]+|\\.)*")|(?:'(?>[^\\']+|\\.)*')|(?:`(?>[^\\`]+|\\.)*`))
 
 # Networking
 MAC (?:%{CISCOMAC}|%{WINDOWSMAC}|%{COMMONMAC})