unexpected behavior of drizzle_error() when using drizzle_set_log_fn()

[Russell Tempero]

In libdrizzle 0.8, if you register a logging function via drizzle_set_log_fn(), the drizzle_error() function no longer returns the last error message. This seem slightly odd and, in our use of these functions, we ran into cases where we wanted both to function together.

I have attached a patch that seems to fix this problem.

[Andrew Hutchings (linuxjedi)]

We highly recommend you don't use 0.8, it has some critical bugs in it. But this appears to affect 1.0 and 2.0 as well