isoBuilder: put installer-requestable packages on the media

Two gaps in how the download list is built.

1. The STIG menu offers "Apply STIG hardening", which makes the installer
   request KS_STIG_PACKAGES at install time. Those names were never added to
   the ISO's own RPMS/, so on a minimal ISO - where downloadPkgs() resolves a
   closure rather than copying every rpm - the packages simply were not there
   and the install failed with "Error(1011) : No matching packages".
   Import the list from stigenable rather than restating the names in a
   package list file; restating them is exactly how the media and the
   installer drifted apart. Imported locally because stigenable pulls in the
   curses UI modules, which need not be a module-level dependency of the ISO
   builder.

2. Packages named via --initrd-pkgs never reached this list either. Only the
   list *file* was parsed, so a package requested on the command line could
   not be installed into the initrd from the ISO's own RPMS/.

Both extend self.pkg_list only, so they land in the ISO's RPMS/ and the
initrd does not grow.

Verified end to end: a minimal ISO built with this carries 290 rpms instead
of 254, including selinux-policy, libselinux-utils, rsyslog, aide,
openssl-fips-provider and ntpsec; the UI wizard's STIG option completes; and
the installed system comes up SELinux Enforcing with 0 failed ansible tasks.

Signed-off-by: Daniel Casota <dcasota@gmail.com>

Author: dcasota

photon_installer/isoBuilder.py

@@ -195,6 +195,22 @@ def downloadPkgs(self):
         # Add installer initrd and custom packages to package list..
         self.addPkgsToList(self.initrd_pkg_list_file)
         self.addPkgsToList(self.packageslist_file)
+        # The media must be able to satisfy what the installer can request at
+        # install time. KS_STIG_PACKAGES is the installer's own declaration of
+        # what "Apply STIG hardening" installs, so import it rather than
+        # restating those names in a package list file -- restating them is how
+        # the media and the installer drifted apart, leaving the STIG menu
+        # offering an option the media could not honour ("Error(1011) : No
+        # matching packages"). Imported locally: stigenable pulls in the curses
+        # UI modules, which need not be a module-level dependency of the ISO
+        # builder. These go to the ISO's RPMS/ only, not into self.initrd_pkgs,
+        # so the initrd does not grow.
+        from stigenable import KS_STIG_PACKAGES
+        self.pkg_list.extend(KS_STIG_PACKAGES)
+        # Packages named via --initrd-pkgs never reached this download list
+        # (only the list *file* was parsed above), so they could not be
+        # installed into the initrd from the ISO's own RPMS/ either.
+        self.pkg_list.extend(self.initrd_pkgs)
 
         linux_flavors = [
             "linux",