ssh_statemach_act: split out assignment from check

just a minor code style thing to make the code clearer

lib/ssh.c

@@ -1793,7 +1793,8 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
       break;
 
     case SSH_SFTP_CREATE_DIRS:
-      if((sshc->slash_pos = strchr(sshc->slash_pos, '/')) != NULL) {
+      sshc->slash_pos = strchr(sshc->slash_pos, '/');
+      if(sshc->slash_pos) {
         *sshc->slash_pos = 0;
 
         infof(data, "Creating directory '%s'\n", sftp_scp->path);