rpm: use the install target in boot/Makefile

Fix the target to install file into /etc/default (it's not grub.d file).
And then don't open-code it in the spec file.
No functional change.

(cherry picked from commit 33e30a1)

boot/Makefile

@@ -1,10 +1,11 @@
 LIBDIR ?= /usr/lib
 SYSCONFDIR ?= /etc
-GRUBCONFDIR ?= $(SYSCONFDIR)/grub.d
+GRUBCONFDIR ?= $(SYSCONFDIR)/default
 DRACUTCONFDIR ?= $(LIBDIR)/dracut/dracut.conf.d
+GRUBCFGNAME ?= grub.qubes
 
 .PHONY: install
 
 install:
-	install -D -m 0644 grub.qubes $(DESTDIR)$(GRUBCONFDIR)/30_qubes
+	install -D -m 0644 grub.qubes $(DESTDIR)$(GRUBCONFDIR)/$(GRUBCFGNAME)
 	install -D -m 0644 dracut-qubes.conf $(DESTDIR)$(DRACUTCONFDIR)/30-qubes.conf

rpm_spec/core-agent.spec.in

@@ -487,6 +487,7 @@ usermod -L root
 
 make install-vm PYTHON=%{__python3} "DESTDIR=$RPM_BUILD_ROOT" SYSTEM_DROPIN_DIR=%{_unitdir} SYSLIBDIR=/usr/lib ENABLE_SELINUX=%with_selinux
 make -C app-menu DESTDIR=$RPM_BUILD_ROOT install
+make -C boot DESTDIR=$RPM_BUILD_ROOT install
 make -C boot/redhat DESTDIR=$RPM_BUILD_ROOT install
 make -C config-overrides DESTDIR=$RPM_BUILD_ROOT install
 make -C filesystem DESTDIR=$RPM_BUILD_ROOT install
@@ -520,9 +521,6 @@ sed -i \
         $RPM_BUILD_ROOT/etc/yum.repos.d/qubes-*.repo
 %endif
 
-install -D -m 0644 boot/dracut-qubes.conf $RPM_BUILD_ROOT/usr/lib/dracut/dracut.conf.d/30-qubes.conf
-install -D -m 0644 boot/grub.qubes $RPM_BUILD_ROOT/etc/default/grub.qubes
-
 %if ! %with_sysvinit
     rm -rf $RPM_BUILD_ROOT/etc/init.d/qubes-* $RPM_BUILD_ROOT/etc/sysconfig/modules/qubes-core.modules
 %endif