signlk: fixup parsing of 'du'

'du' utility from coreutils uses TAB for delimiter, not SPACE, make the parsing
more robust.

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

signlk.sh

@@ -159,12 +159,12 @@ openssl x509 -in $tmpdir/atte_cert.PEM -inform PEM -outform DER > $ATT 2>/dev/nu
 openssl pkeyutl -sign -inkey $tmpdir/atte_key.PEM -in $CODE > $SIG 2>/dev/null
 
 
-data_file_size=$( cut -d ' ' -f 1 <<< $(du -b $DATA) )
-code_file_size=$( cut -d ' ' -f 1 <<< $(du -b $CODE) )
-sig_file_size=$( cut -d ' ' -f 1 <<< $(du -b $SIG) )
-atte_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ATT) )
-root_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ROOT) )
-hash_seg_file_size=$( cut -d ' ' -f 1 <<< $(du -b $tmpdir/hashSeg) )
+data_file_size=$( cut -d ' ' -f 1 <<< $(du -b $DATA | tr '[:blank:]' ' '))
+code_file_size=$( cut -d ' ' -f 1 <<< $(du -b $CODE | tr '[:blank:]' ' ') )
+sig_file_size=$( cut -d ' ' -f 1 <<< $(du -b $SIG | tr '[:blank:]' ' ') )
+atte_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ATT | tr '[:blank:]' ' ') )
+root_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ROOT | tr '[:blank:]' ' ') )
+hash_seg_file_size=$( cut -d ' ' -f 1 <<< $(du -b $tmpdir/hashSeg | tr '[:blank:]' ' ') )
 hash_seg_offset=4096
 mi_hdr_size=40