flux-kvs: remove dropcache command

Problem: The kvs.dropcache RPC target no longer exists, yet
the "flux kvs dropcache" command still exists.

Remove "flux kvs dropcache" support.

Author: chu11

src/cmd/flux-kvs.c

@@ -42,7 +42,6 @@ int cmd_readlink (optparse_t *p, int argc, char **argv);
 int cmd_mkdir (optparse_t *p, int argc, char **argv);
 int cmd_version (optparse_t *p, int argc, char **argv);
 int cmd_wait (optparse_t *p, int argc, char **argv);
-int cmd_dropcache (optparse_t *p, int argc, char **argv);
 int cmd_copy (optparse_t *p, int argc, char **argv);
 int cmd_move (optparse_t *p, int argc, char **argv);
 int cmd_dir (optparse_t *p, int argc, char **argv);
@@ -184,13 +183,6 @@ static struct optparse_option ls_opts[] =  {
     OPTPARSE_TABLE_END
 };
 
-static struct optparse_option dropcache_opts[] =  {
-    { .name = "all", .key = 'a', .has_arg = 0,
-      .usage = "Drop KVS across all ranks",
-    },
-    OPTPARSE_TABLE_END
-};
-
 static struct optparse_option unlink_opts[] =  {
     { .name = "namespace", .key = 'N', .has_arg = 1,
       .usage = "Specify KVS namespace to use.",
@@ -360,13 +352,6 @@ static struct optparse_subcommand subcommands[] = {
       0,
       copy_opts
     },
-    { "dropcache",
-      "[--all]",
-      "Tell KVS to drop its cache",
-      cmd_dropcache,
-      0,
-      dropcache_opts
-    },
     { "version",
       "[-N ns]",
       "Display current KVS version",
@@ -1213,27 +1198,6 @@ int cmd_wait (optparse_t *p, int argc, char **argv)
     return (0);
 }
 
-int cmd_dropcache (optparse_t *p, int argc, char **argv)
-{
-    flux_t *h;
-
-    if (!(h = flux_open (NULL, 0)))
-        log_err_exit ("flux_open");
-
-    if (optparse_hasopt (p, "all")) {
-        flux_msg_t *msg = flux_event_encode ("kvs.dropcache", NULL);
-        if (!msg || flux_send (h, msg, 0) < 0)
-            log_err_exit ("flux_send");
-        flux_msg_destroy (msg);
-    }
-    else {
-        if (flux_kvs_dropcache (h) < 0)
-            log_err_exit ("flux_kvs_dropcache");
-    }
-    flux_close (h);
-    return (0);
-}
-
 static char *process_key (const char *key)
 {
     char *nkey;