4171 clean up spa_feature_*() interfaces
4172 implement extensible_dataset feature for use by other zpool features
Reviewed by: Max Grossman <max.grossman@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

@@ -570,11 +570,11 @@
         kmem_free(mzp, sz);
         *zapp = zap;
         return (err);
 }
 
-static void
+void
 mzap_create_impl(objset_t *os, uint64_t obj, int normflags, zap_flags_t flags,
     dmu_tx_t *tx)
 {
         dmu_buf_t *db;
         mzap_phys_t *zp;

@@ -860,12 +860,12 @@
 }
 
 int
 zap_contains(objset_t *os, uint64_t zapobj, const char *name)
 {
-        int err = (zap_lookup_norm(os, zapobj, name, 0,
-            0, NULL, MT_EXACT, NULL, 0, NULL));
+        int err = zap_lookup_norm(os, zapobj, name, 0,
+            0, NULL, MT_EXACT, NULL, 0, NULL);
         if (err == EOVERFLOW || err == EINVAL)
                 err = 0; /* found, but skipped reading the value */
         return (err);
 }