Fix invalid efree in browscap

Related to bug #77338.

ext/standard/browscap.c

@@ -713,7 +713,7 @@ PHP_FUNCTION(get_browser)
 			found_entry = zend_hash_str_find_ptr(bdata->htab,
 				DEFAULT_SECTION_NAME, sizeof(DEFAULT_SECTION_NAME)-1);
 			if (found_entry == NULL) {
-				efree(lookup_browser_name);
+				zend_string_release(lookup_browser_name);
 				RETURN_FALSE;
 			}
 		}

ext/standard/tests/misc/browscap_no_default.ini

@@ -0,0 +1,2 @@
+[Firefox]
+Browser="Firefox"

ext/standard/tests/misc/get_browser_no_default.phpt

@@ -0,0 +1,12 @@
+--TEST--
+get_browser() without a default
+--INI--
+browscap={PWD}/browscap_no_default.ini
+--FILE--
+<?php
+
+var_dump(get_browser(""));
+
+?>
+--EXPECT--
+bool(false)