tree-wide: use -EBADF for fd initialization

-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.

Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state

Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.

In some places, initialization is dropped if unnecessary.

src/nspawn/nspawn-patch-uid.c

@@ -28,7 +28,7 @@ static int get_acl(int fd, const char *name, acl_type_t type, acl_t *ret) {
         assert(ret);
 
         if (name) {
-                _cleanup_close_ int child_fd = -1;
+                _cleanup_close_ int child_fd = -EBADF;
 
                 child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
                 if (child_fd < 0)
@@ -53,7 +53,7 @@ static int set_acl(int fd, const char *name, acl_type_t type, acl_t acl) {
         assert(acl);
 
         if (name) {
-                _cleanup_close_ int child_fd = -1;
+                _cleanup_close_ int child_fd = -EBADF;
 
                 child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
                 if (child_fd < 0)