libkvs: remove flux_kvs_dropcache()

Problem: The kvs.dropcache RPC target has been removed, but the
library function flux_kvs_dropcache() still exists.

Remove flux_kvs_dropcache() from libkvs.

Author: chu11

src/common/libkvs/kvs.c

@@ -162,21 +162,6 @@ int flux_kvs_wait_version (flux_t *h, const char *ns, int version)
     return ret;
 }
 
-int flux_kvs_dropcache (flux_t *h)
-{
-    flux_future_t *f;
-    int rc = -1;
-
-    if (!(f = flux_rpc (h, "kvs.dropcache", NULL, FLUX_NODEID_ANY, 0)))
-        goto done;
-    if (flux_future_get (f, NULL) < 0)
-        goto done;
-    rc = 0;
-done:
-    flux_future_destroy (f);
-    return rc;
-}
-
 /*
  * vi:tabstop=4 shiftwidth=4 expandtab
  */

src/common/libkvs/kvs.h

@@ -66,12 +66,6 @@ flux_future_t *flux_kvs_namespace_remove (flux_t *h, const char *ns);
 int flux_kvs_get_version (flux_t *h, const char *ns, int *versionp);
 int flux_kvs_wait_version (flux_t *h, const char *ns, int version);
 
-/* Garbage collect the cache.  Drop all data that doesn't have a
- * reference in the namespace.
- * Returns -1 on error (errno set), 0 on success.
- */
-int flux_kvs_dropcache (flux_t *h);
-
 #ifdef __cplusplus
 }
 #endif