app: utils: Don't limit size of data in multipart mimes
app: utils: Don't limit size of data in multipart mimes

In process_mime_part() for non file data we were reading in BUF_SIZE
data from the POST.

Instead allocate buf dynamically with malloc() using the bytes value
returned from g_mime_data_wrapper_write_to_stream() for amount + 1 for
the null byte, which isn't technically required due to subsequent
strdup's adding it themselves.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@opentechlabs.co.uk>

ac000/fcgi_app_core,ac000/fcgi_app_core