Fix GLib critical warning about default enum value not found

LOGSEVERITY_DEFAULT is defined as a different enum value as
LOGSEVERITY_INFO, which it corresponds to, and set as equal later on
internally. This cannot work when looking it up in the GEnumValue array.
Easiest way around it is to manually set it to INFO.

gstcefsrc.cc

@@ -31,7 +31,7 @@ GST_DEBUG_CATEGORY_STATIC (cef_console_debug);
 #define DEFAULT_URL "https://www.google.com"
 #define DEFAULT_GPU FALSE
 #define DEFAULT_CHROMIUM_DEBUG_PORT -1
-#define DEFAULT_LOG_SEVERITY LOGSEVERITY_DEFAULT
+#define DEFAULT_LOG_SEVERITY LOGSEVERITY_INFO
 #if !defined(__APPLE__) && defined(GST_CEF_USE_SANDBOX)
 #define DEFAULT_SANDBOX TRUE
 #else