Blank out Google Analytics account information from clientserver edition

This also fixes a recently introduced problem: when I removed the last
`.tid` file from the `editions/clientserver/tiddlers/` directory, git
promptly stopped recording the directory in commits, and so newly
downloaded copies of the repo lacked the directory. That caused the
filesystemadaptor to fail to save newly created tiddlers.

editions/clientserver/tiddlers/system/GoogleAnalyticsAccount.tid

@@ -0,0 +1,2 @@
+title: $:/GoogleAnalyticsAccount
+

editions/clientserver/tiddlers/system/GoogleAnalyticsDomain.tid

@@ -0,0 +1,2 @@
+title: $:/GoogleAnalyticsDomain
+