pvv_is_int(): Be even more flexible

This patch further improves commit 6191f27, where the macro will now
also work with code such as:

(excerpt from pv_set_count()):
    ...
    pv_val.flags = PV_TYPE_INT;
    pv_val.ri = pv_name->pvp.pvi.u.ival-1;
    ...

Notice how the flags are poorly set, since the PV_VAL_INT bit should
have been used instead.

(cherry picked from commit 34af3c4)

pvar.h

@@ -61,7 +61,7 @@
 
 /* @v: a (pv_value_t *) */
 #define pvv_is_int(v) \
-	((v)->flags & PV_VAL_INT && \
+	((v)->flags & (PV_VAL_INT|PV_TYPE_INT) && \
 		((v)->flags & PV_TYPE_INT || !((v)->flags & PV_VAL_STR)))
 #define pvv_is_str(v) \
 	((v)->flags & PV_VAL_STR && !((v)->flags & PV_TYPE_INT))