D-Bus: Fix string array dict entry parser in out-of-memory case

D-Bus: Fix string array dict entry parser in out-of-memory case

entry->strarray_value was left to point to freed memory in case
os_realloc_array() failed. This resulted in the following
wpa_dbus_dict_entry_clear() trying to free an already freed memory area.
In addition, the separately allocated strings in the array would have
been leaked in such a case. Furthermore, wpa_dbus_dict_entry_clear() was
not prepared for the possibility of the initial os_calloc() call failing
and entry->strarray_value being NULL without array_len being cleared to
zero. That would have resulted in reading uninitialized memory and NULL
pointer dereference.

Signed-off-by: Jouni Malinen <j@w1.fi>