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.

src/shared/install.c

@@ -1553,10 +1553,8 @@ int unit_file_add_dependency(
                 UnitFileState state;
 
                 state = unit_file_get_state(scope, root_dir, *i);
-                if (state < 0) {
-                        log_error_errno(state, "Failed to get unit file state for %s: %m", *i);
-                        return state;
-                }
+                if (state < 0)
+                        return log_error_errno(state, "Failed to get unit file state for %s: %m", *i);
 
                 if (state == UNIT_FILE_MASKED || state == UNIT_FILE_MASKED_RUNTIME) {
                         log_error("Failed to enable unit: Unit %s is masked", *i);