kernel: multiple fixes for building modules via kernel-headers.

--HG--
extra : convert_revision : b827833cddca2581edb20ceb170863082d8ae223

srcpkgs/kernel/kernel-headers.template

@@ -5,8 +5,12 @@ long_desc="
  This package contains the required source headers to be able to build
  external 3rd party binary modules."
 
+if [ -n "${_kernel_headers_revision}" ]; then
+	revision=${_kernel_headers_revision}
+fi
+
 do_install()
 {
-	mkdir -p ${DESTDIR}/usr
-	mv ${SRCPKGDESTDIR}/usr/src ${DESTDIR}/usr
+	mkdir -p ${DESTDIR}
+	mv ${SRCPKGDESTDIR}/usr ${DESTDIR}
 }