Alert params for 0.5.0 through 0.5.3

alertparams.cpp

    alert.nRelayUntil   = GetTime() + 15 * 60;
    alert.nExpiration   = GetTime() + 365 * DAYS;
    alert.nID           = 1011;
    alert.nCancel       = 1010;   // cancels previous messages up to this ID number                                                                                  
    alert.nMinVer       = 50000;
    alert.nMaxVer       = 50300;
    alert.nPriority     = 5000;
    alert.strComment    = "";
    alert.strStatusBar  = "URGENT: security fix for Bitcoin-Qt on Windows: http://bitcoin.org/critfix";