object-file: convert 'switch' back to 'if'

This switch statement was recently added to make it clear that
unpack_loose_header() returns an enum value, not an int. This adds
complications for future developers if that enum gains new values, since
that developer would need to add a case statement to this switch for
little real value.

Instead, we can revert back to an 'if' statement, but make the enum
explicit by using "!= ULHR_OK" instead of assuming it has the numerical
value zero.

Co-authored-by: Junio C Hamano <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

object-file.c

@@ -2623,12 +2623,8 @@ int read_loose_object(const char *path,
 		goto out;
 	}
 
-	switch (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
-				    NULL)) {
-	case ULHR_OK:
-		break;
-	case ULHR_BAD:
-	case ULHR_TOO_LONG:
+	if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
+				NULL) != ULHR_OK) {
 		error(_("unable to unpack header of %s"), path);
 		goto out;
 	}