treewide: yet more log_*_errno + return simplifications

Using:
find . -name '*.[ch]' | while read f; do perl -i.mmm -e \
 'local $/;
  local $_=<>;
  s/(if\s*\([^\n]+\))\s*{\n(\s*)(log_[a-z_]*_errno\(\s*([->a-zA-Z_]+)\s*,[^;]+);\s*return\s+\g4;\s+}/\1\n\2return \3;/msg;
  print;'
 $f
done

And a couple of manual whitespace fixups.