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/basic/chattr-util.c

@@ -20,7 +20,7 @@ int chattr_full(const char *path,
                 unsigned *ret_final,
                 ChattrApplyFlags flags) {
 
-        _cleanup_close_ int fd_will_close = -1;
+        _cleanup_close_ int fd_will_close = -EBADF;
         unsigned old_attr, new_attr;
         int set_flags_errno = 0;
         struct stat st;
@@ -149,7 +149,7 @@ int read_attr_fd(int fd, unsigned *ret) {
 }
 
 int read_attr_path(const char *p, unsigned *ret) {
-        _cleanup_close_ int fd = -1;
+        _cleanup_close_ int fd = -EBADF;
 
         assert(p);
         assert(ret);