samhain-server: do not extend to native

No packages depend on samhain-server-native and it doesn't
make sense to extend a server package to native, so remove
the BBCLASSEXTEND.

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

recipes-security/samhain/samhain-server_4.2.2.bb

@@ -18,4 +18,3 @@ do_install_append() {
 }
 
 RDEPENDS_${PN} += "gmp bash perl"
-BBCLASSEXTEND = "native"