file: remove unnecessary uci_fixup_section calls

file: remove unnecessary uci_fixup_section calls

This makes it clear uci_fixup_section only needs to be called in
uci_add_section when an unnamed section is added.

Before it was a bit misleading when walking through the code seeing
uci_fixup_section being called in uci_parse_config and uci_import.
When uci config is parsed via these functions uci_add_section is
eventually called which in the end constructs a name for an unnamed
section.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>