gbase64: Remove an unnecessary condition
gbase64: Remove an unnecessary condition

At that point in the code, len can only be 0, 1 or 2. The code below is
a no-op if (len == 0), so the condition is pointless.

Remove it, and we should be able to achieve full branch coverage of
gbase64.c.

This should introduce no functional changes.

Signed-off-by: Philip Withnall <29c2a2ac2a854b9cf047275aa9de346d096be2e0@endlessm.com>

endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib