vmcheck: fixes for CentOS 7

The `install` command in CentOS 7 is too old to understand that
`-Dt foo/bar` means creating both `foo` and `bar`, which is useful so
that we avoid an explicit `mkdir` before. But we can't do that here.

Closes: #871
Approved by: cgwalters

tests/vmcheck/test-layering-non-root-caps.sh

@@ -36,9 +36,11 @@ vm_build_rpm nonrootcap \
            done" \
     pre "groupadd -r nrcgroup
          useradd -r nrcuser -g nrcgroup -s /sbin/nologin" \
-    install "install -Dt %{buildroot}/etc nrc.conf
+    install "mkdir -p %{buildroot}/etc
+             install nrc.conf %{buildroot}/etc
              ln -sr %{buildroot}/etc/nrc.conf %{buildroot}/etc/nrc-link.conf
-             install -Dt %{buildroot}/usr/bin *.sh
+             mkdir -p %{buildroot}/usr/bin
+             install *.sh %{buildroot}/usr/bin
              ln -sr %{buildroot}/usr/bin/{nrc-user.sh,nrc-user-link.sh}
              mkdir -p %{buildroot}/var/lib/nonrootcap
              mkdir -p %{buildroot}/run/nonrootcap

tests/vmcheck/test-livefs.sh

@@ -52,7 +52,8 @@ echo "ok livefs stage1"
 
 vm_build_rpm test-livefs-with-etc \
   build 'echo "A config file for %{name}" > %{name}.conf' \
-  install 'install -Dt %{buildroot}/etc %{name}.conf
+  install 'mkdir -p %{buildroot}/etc
+           install %{name}.conf %{buildroot}/etc
            mkdir -p %{buildroot}/etc/%{name}/
            echo subconfig-one > %{buildroot}/etc/%{name}/subconfig-one.conf
            echo subconfig-two > %{buildroot}/etc/%{name}/subconfig-two.conf