sync testing: create Client_Sync_Current symlink for server

A SyncEvolution HTTP server running locally can be configured (outside
of client-test!) to use "Client_Sync_Current" as logdir. That symlink
will be pointed to a new, clean directory each time a sync runs. That
way it becomes possible to associate the server side of a
SyncEvolution<->SyncEvolution test with the specific test logs on the
client side.

src/client-test-app.cpp

@@ -332,6 +332,15 @@ public:
     {
         init();
 
+        // Let "Client_Sync_Current" symlink point to a new, empty
+        // directory logbase + ".server". Can be used by SyncEvolution
+        // server as per-test logdir.
+        std::string current = logbase + ".server";
+        rm_r(current);
+        mkdir_p(current);
+        rm_r("Client_Sync_Current");
+        symlink(current.c_str(), "Client_Sync_Current");
+
         // check whether using buteo to do sync
         const char *buteo = getenv("CLIENT_TEST_BUTEO");
         bool useButeo = false;