openscap: fix scap-security-guide build error

It would fail to build scap-security-guide when use openscap-native
sstate cache.

Steps to reproduce:
Create a new build project:
$ bitbake openscap-native
$ bitbake openscap-native -c clean
$ bitbake scap-security-guide

Error message:
OpenSCAP Error: Schema file 'xccdf/1.1/xccdf-schema.xsd' not found in path
'/buildarea/build/tmp/work-shared/openscap/oscap-build-artifacts/usr/share/openscap/schemas'
when trying to validate
'/buildarea/build/tmp/work/core2-64-poky-linux/scap-security-guide/0.1.44+gitAUTOINC+5fdfdcb2e9-r0/git/build/chromium/xccdf-unlinked-resolved.xml'
[/buildarea/build/tmp/work/x86_64-linux/openscap-native/1.3.1+gitAUTOINC+4bbdb46ff6-r0/git/src/source/validate.c:104]
Invalid XCCDF Checklist (1.1) content in
/buildarea/build/tmp/work/core2-64-poky-linux/scap-security-guide/0.1.44+gitAUTOINC+5fdfdcb2e9-r0/git/build/chromium/xccdf-unlinked-resolved.xml.
[/buildarea/build/tmp/work/x86_64-linux/openscap-native/1.3.1+gitAUTOINC+4bbdb46ff6-r0/git/src/source/oscap_source.c:346]
chromium/CMakeFiles/generate-internal-chromium-xccdf-unlinked-resolved.xml.dir/build.make:63: recipe for target 'chromium/xccdf-unlinked-resolved.xml' failed

When using sstate cache, the openscap-native doesn't install the
artifacts to work-shared/openscap/oscap-build-artifacts when prepare
recipe sysroot for scap-security-guide.

Set do_install[nostamp] to 1 to ensure the openscap-native artifacts
are installed to work-shared/openscap/oscap-build-artifacts even if
using sstate cache.

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-security-compliance/recipes-openscap/openscap/openscap.inc

@@ -41,6 +41,7 @@ do_configure_append_class-native () {
 }
 
 do_clean[cleandirs] += "${STAGING_OSCAP_BUILDDIR}"
+do_install[nostamp] = "1"
 
 do_install_append_class-native () {
     oscapdir=${STAGING_OSCAP_BUILDDIR}/${datadir_native}