First, cb751012 mistakenly converted the
act_stage_context_step() in connect_ready() to connect_context_clear()
instead of connect_context_step().  This would cause the IP Type retry
logic to fail and no further types to be tried.  It also throws
away the ctx->first_error and causes all errors that MM returns on the
connect attempt to be dropped on the floor.

Second, not all errors should cause an advance to the next IP Type,
since some errors aren't related to it.  Specifically, MM_CORE_ERROR_RETRY
when using Simple.Connect() means that a timeout was reached
in the internal connect logic, not a modem or network error.  In
that case, try the connect again with the same IP Type before advancing
to the next type.

Fixes: cb751012



Tested-by: Ladislav Michl <ladis@linux-mips.org>
Tested-by: Tore Anderson <tore@fud.no>