shim 15.4

This is a critical bugfix release.  Don't use 15.3, as the SBAT self-check is
broken.

Many thanks to all who helped out, including but not limited to these
contributions:

Chris Co (1):
      Makefile: sort vendor sbats to remove duplicates

Jan Setje-Eilers (3):
      Move the check for the SBAT variable properties to its own function.
      Fix SBAT variable content validation.
      Change SBAT variable name to SbatLevel

Peter Jones (13):
      CI: don't use 'make -s'; it's more trouble than help.
      arm/aa64: Swizzle some sections to make old sbsign happier.
      Make building outside of the top directory work.
      make: make 'make install-as-data' install BOOT*.CSV
      make: Fix search paths for vendor sbat.*.csv files
      test_parse_sbat_section_too_many_elem(): free section entries
      parse_sbat_var_data()/cleanup_sbat_var(): fix free logic
      test_verify_sbat_null_sbat_section(): call cleanup_sbat_var()
      Fix openssl's 'make clean'
      sbat: add more dprint()
      arm/aa64 targets: put .rel* and .dyn* in .rodata
      Fix an off-by-one on the sbat self-check.
      Update version to 15.4
-----BEGIN PGP SIGNATURE-----

iQJGBAABCgAwFiEEsAtIvHMaqIQP7Z+w7tJmtw9P7xAFAmBjkXwSHHBqb25lc0By
ZWRoYXQuY29tAAoJEO7SZrcPT+8Qe/gP/2AkMXLu+JVTKNy3ysreY7c8UzaIgdxa
lZ19nzcRc8Qca696PvI2NmTQIiLedusWso43qHAtZxiMaftgbKkQf4syxONhXoKC
iXrOot29MV2e2pOu8tiLZ4jSUYHs++UXja120H0M7w+/nAgPZlJV3sx12HkgtIHl
UZuAs0BWze7aiQX5T/iKZetH1aDNBpYHh7FgHCdRw5BThMkd3K0NUWSUxC3kYiXd
5/uDqyEnKcL/I0jodOESP3RXKrffoOnHoxH0a9yEF+yp1JtDkah6z4K+PPfR28Hv
yjGP4cyu2AuQzh1NUorzim9Ga3TyBmNyX+Vz2EAEynBK8Y5U1z/YkfMNC3ETLg3A
6ICdhFW6X7CcBNU1+Fg0PTizqe0KhHnY08SrzN91QqmT2TH6UjnOqtV4WpIXSjGP
DHXPsk+wr1yuX31DWPziI6DugD7v/u3hmADzMKCAHVKQ68rKpgbZehRv4myiU4gn
qYaqKWvvPkDu9lSnMVZ2HcedlGwEZKwvPSv1KY9E0owMYnnCALcldxmMPxwSId4I
p+JaZWT59gAjYM/LGgvlY+WIU/EiLVQLZqkDg0Ghh/1Z7pTiNLIOrW1RZxi9YXjG
l1zHOqA0NLdbJxLiZo79V+hU4a+CYEZnP1iIBiQZOkWXCrzZh1ONCpopaIeJYnX+
W3xHIlKhCfqy
=khiA
-----END PGP SIGNATURE-----