bot_kick in nav_generate instead of game-specific commands

[gru2007]

source-sdk-2013/src/game/server/nav_generate.cpp

Line 3437 in fe72581

engine->ServerCommand( "bot_kick\n" );

This command need to be switched to tf_bot_kick all or hl2mp_bot_kick all, otherwise there is an error of kicking bots.