Fix HEREDOC bug

Summary:
Heredocs weren't scanning properly in XHP 1.2.1. This fixes that

Test Plan:
$foo = <<<HERE
HERE;

Reviewed By: epriestley

Revert: OK

ext.hpp

@@ -4,7 +4,7 @@
 #endif
 #include "php.h"
 
-#define PHP_XHP_VERSION "1.2.1"
+#define PHP_XHP_VERSION "1.2.2"
 #define PHP_XHP_EXTNAME "xhp"
 
 extern zend_module_entry xhp_module_entry;

xhp/scanner.l

@@ -444,6 +444,7 @@ NEWLINE ("\r\n"|"\n"|"\r")
     }
     ++yyextra->lineno;
     yyextra->heredoc_yyleng = yyleng;
+    yymore();
   }
   [^\r\n]+ {
     set_state(PHP_HEREDOC_DATA);