build: introduce XEN_RUN_STORED

It defaults to /var/run/xenstored. It will be used later to remove some
hard-coded paths in tree. There should be no visible change to default
configuration.

Install and remove it in respective Makefile targets.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

m4/paths.m4

@@ -107,6 +107,9 @@ AC_SUBST(XEN_LOG_DIR)
 XEN_LIB_STORED=$localstatedir/lib/xenstored
 AC_SUBST(XEN_LIB_STORED)
 
+XEN_RUN_STORED=$localstatedir/run/xenstored
+AC_SUBST(XEN_RUN_STORED)
+
 XEN_LIB_DIR=$localstatedir/lib/xen
 AC_SUBST(XEN_LIB_DIR)