makedevs: allow leading whitespace for capabilities

Currently makedevs silently ignores extended attributes with leading
whitespace, for example those added to a <PACKAGE>_PERMISSIONS following
the recommended style from check-package.

Makedevs already ignores leading whitespace for normal entries (file
permission changes and device files creation). Do the same for extended
attributes.

Fixes: #11191.

Reported-by: Jean-pierre Cartal <jpcartal@free.fr>
Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/makedevs/makedevs.c

@@ -510,7 +510,7 @@ int main(int argc, char **argv)
 
 		linenum++;
 
-		if (1 == sscanf(line, "|xattr %254s", xattr)) {
+		if (1 == sscanf(line, " |xattr %254s", xattr)) {
 #ifdef EXTENDED_ATTRIBUTES
 			if (!full_name)
 				bb_error_msg_and_die("line %d should be after a file\n", linenum);