Fix set but not used variable

Author: kocsismate

ext/intl/grapheme/grapheme_string.cpp

@@ -1136,7 +1136,7 @@ U_CFUNC PHP_FUNCTION(grapheme_strrev)
 	UText *ut = nullptr;
 	UErrorCode ustatus = U_ZERO_ERROR;
 	UBreakIterator *bi;
-	char *pstr, *end, *p;
+	char *pstr, *p;
 	zend_string *ret;
 	int32_t pos = 0, current = 0, end_len = 0;