Change -genproclimit default to 1

This is less surprising.

Avoids the overload-the-CPU default of using N threads for script
verification as well as N threads for generation where N is number of cores.

src/init.cpp

@@ -320,7 +320,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += ".\n";
 #ifdef ENABLE_WALLET
     strUsage += "  -gen                   " + strprintf(_("Generate coins (default: %u)"), 0) + "\n";
-    strUsage += "  -genproclimit=<n>      " + strprintf(_("Set the processor limit for when generation is on (-1 = unlimited, default: %d)"), -1) + "\n";
+    strUsage += "  -genproclimit=<n>      " + strprintf(_("Set the number of threads for coin generation if enabled (-1 = all cores, default: %d)"), 1) + "\n";
 #endif
     strUsage += "  -help-debug            " + _("Show all debugging options (usage: --help -help-debug)") + "\n";
     strUsage += "  -logips                " + strprintf(_("Include IP addresses in debug output (default: %u)"), 0) + "\n";
@@ -1263,7 +1263,7 @@ bool AppInit2(boost::thread_group& threadGroup)
 #ifdef ENABLE_WALLET
     // Generate coins in the background
     if (pwalletMain)
-        GenerateBitcoins(GetBoolArg("-gen", false), pwalletMain, GetArg("-genproclimit", -1));
+        GenerateBitcoins(GetBoolArg("-gen", false), pwalletMain, GetArg("-genproclimit", 1));
 #endif
 
     // ********************************************************* Step 11: finished