rpc: Revert Coverity tag message

Turns out the fix for VIR_FREE made this particular Coverity tag
unnecessary, so I'm removing it.

src/rpc/virnetclient.c

@@ -430,7 +430,6 @@ virNetClientPtr virNetClientNewLibSSH2(const char *host,
                 VIR_FREE(privkey);
             /* DSA */
             if (!privkey) {
-                /* coverity[dead_error_begin] */
                 virBufferAsprintf(&buf, "%s/.ssh/id_dsa", homedir);
                 if (!(privkey = virBufferContentAndReset(&buf)))
                     goto no_memory;