HTTPDATE is used by patterns/aws

Fixes #102

Author: chernjie

patterns/grok-patterns

@@ -83,6 +83,7 @@ PROG [\x21-\x5a\x5c\x5e-\x7e]+
 SYSLOGPROG %{PROG:program}(?:\[%{POSINT:pid}\])?
 SYSLOGHOST %{IPORHOST}
 SYSLOGFACILITY <%{NONNEGINT:facility}.%{NONNEGINT:priority}>
+HTTPDATE %{MONTHDAY}/%{MONTH}/%{YEAR}:%{TIME} %{INT}
 
 # Shortcuts
 QS %{QUOTEDSTRING}

patterns/httpd

@@ -1,6 +1,5 @@
 HTTPDUSER %{EMAILADDRESS}|%{USER}
 HTTPDERROR_DATE %{DAY} %{MONTH} %{MONTHDAY} %{TIME} %{YEAR}
-HTTPDATE %{MONTHDAY}/%{MONTH}/%{YEAR}:%{TIME} %{INT}
 
 # Log formats
 HTTPD_COMMONLOG %{IPORHOST:clientip} %{HTTPDUSER:ident} %{HTTPDUSER:auth} \[%{HTTPDATE:timestamp}\] "(?:%{WORD:verb} %{NOTSPACE:request}(?: HTTP/%{NUMBER:httpversion})?|%{DATA:rawrequest})" %{NUMBER:response} (?:%{NUMBER:bytes}|-)