Auto merge of #2203 - arcalinea:2142_security_log_message, r=daira

Add message directing users to security guide

Addresses #2142, which was blocking on updates to zcash/support/security.html. That page has now been added, so this message directing users to the site can be included.

It displays in the zcash-cli --help and --version message text, and on the zcashd metrics screen.

src/util.cpp

@@ -888,9 +888,17 @@ void SetThreadPriority(int nPriority)
 #endif // WIN32
 }
 
+std::string PrivacyInfo()
+{
+    return "\n" +
+           FormatParagraph(strprintf(_("In order to ensure you are adequately protecting your privacy when using Zcash, please see <%s>."),
+                                     "https://z.cash/support/security/index.html")) + "\n";
+}
+
 std::string LicenseInfo()
 {
-    return FormatParagraph(strprintf(_("Copyright (C) 2009-%i The Bitcoin Core Developers"), COPYRIGHT_YEAR)) + "\n" +
+    return "\n" +
+           FormatParagraph(strprintf(_("Copyright (C) 2009-%i The Bitcoin Core Developers"), COPYRIGHT_YEAR)) + "\n" +
            FormatParagraph(strprintf(_("Copyright (C) 2015-%i The Zcash Developers"), COPYRIGHT_YEAR)) + "\n" +
            "\n" +
            FormatParagraph(_("This is experimental software.")) + "\n" +