[build] Fix hash comparison using newer versions of pesign

Newer versions of pesign will include the input filename within the
output hash line (presumably in order to match the behaviour of
utilities such as md5sum and sha1sum).  This breaks our existing hash
comparison logic.

Fix by extracting only the hash value from the output line.

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>

src/Makefile

@@ -22,6 +22,7 @@ RM		:= rm
 GCAB		:= gcab
 PESIGN		:= pesign
 DIFF		:= diff
+CUT		:= cut
 BINUTILS_DIR	:= /usr
 BFD_DIR		:= $(BINUTILS_DIR)
 ZLIB_DIR	:= /usr
@@ -86,13 +87,13 @@ wimboot.%.unsigned : wimboot.%.elf efireloc Makefile
 	./efireloc $< $@
 
 wimboot.%.unsigned.hash : wimboot.%.unsigned Makefile
-	$(PESIGN) -h -i $< > $@
+	$(PESIGN) -h -i $< | $(CUT) -d" " -f2- > $@
 
 wimboot.%.efi : wimboot.%.unsigned Makefile
 	$(CP) $< $@
 
 wimboot.%.efi.hash : wimboot.%.efi Makefile
-	$(PESIGN) -h -i $< > $@
+	$(PESIGN) -h -i $< | $(CUT) -d" " -f2- > $@
 
 wimboot.% : wimboot.%.efi wimboot.%.efi.hash wimboot.%.unsigned.hash Makefile
 	$(DIFF) wimboot.$*.efi.hash wimboot.$*.unsigned.hash