*: convert amenable fdopen calls to take_fdopen

Mechanical change to eliminate some cruft by using the
new take_fdopen{_unlocked}() wrappers where trivial.

src/shared/install.c

@@ -1280,10 +1280,9 @@ static int unit_file_load(
         if (r < 0)
                 return r;
 
-        f = fdopen(fd, "r");
+        f = take_fdopen(&fd, "r");
         if (!f)
                 return -errno;
-        fd = -1;
 
         /* c is only needed if we actually load the file (it's referenced from items[] btw, in case you wonder.) */
         assert(c);