Rework datastore tests

Sysrepo now supports parallelized tests. Use the new environmental
variables to implement this in netconf-cli. All of the tests now get
their own clean environment:

- Fresh repository and separate shm prefix. These get cleaned before and
after tests. The only thing that gets left are some empty directories.

- Its own model to test on.

- Separate Netopeer2 daemon: only for netconf tests - that means no
`sleep 5` for sysrepo-only tests. So no useless waiting. Wow! The daemon
also runs with its argv[0] changed to something recognizable for
`pkill`. That means that if Netopeer2 crashes for some reason, pkill
will notify me.

Side note: These changes somehow changed some of the linking, so hopefully I got
those right.

Change-Id: Ib0e582ef03fc559b24203af8afb2a295a6318ca9
diff --git a/tests/data_query.cpp b/tests/data_query.cpp
index d6435a8..4aa597e 100644
--- a/tests/data_query.cpp
+++ b/tests/data_query.cpp
@@ -13,7 +13,6 @@
 #include "sysrepo_access.hpp"
 #elif defined(netconf_BACKEND)
 #include "netconf_access.hpp"
-#include "netopeer_vars.hpp"
 #elif defined(yang_BACKEND)
 #include "yang_access.hpp"
 #include "yang_access_test_vars.hpp"
@@ -40,7 +39,8 @@
 #ifdef sysrepo_BACKEND
     SysrepoAccess datastore(Datastore::Running);
 #elif defined(netconf_BACKEND)
-    NetconfAccess datastore(NETOPEER_SOCKET_PATH);
+    const auto NETOPEER_SOCKET = getenv("NETOPEER_SOCKET");
+    NetconfAccess datastore(NETOPEER_SOCKET);
 #elif defined(yang_BACKEND)
     YangAccess datastore;
     datastore.addSchemaDir(schemaDir);