Removed typo in seafile-controller.c, removed segfault in common/log.c

seafile-controller.c: Now short_opts correctly contains upper case L instead of lower case l (option for setting log file path).

common/log.c: In case the log file is not available (wrong path, no permissions, etc..) the callbacks registered with g_log_default_handler are called anyway and try to write to a nullptr in seafile_log(...) and ccnet_log(...) via logfp which results in a segmentation fault. Now the messages are sent to stdout.