explicit vhosts: only check context for flag
explicit vhosts: only check context for flag

Although the test apps reuse the context info directly and so inherit the
flag state there when creating vhosts, users might generate a fresh info
without the flag for vhost creation.  So just go by what was given at
context creation time.
sartura/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,sartura/libwebsockets