database: Initialize system keyspace in database constructor

System keyspace is used for things like keyspace and table metadata.
Initialize it in database constructor so that they're always available.
Needed for CQL create keyspace test case, for example.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

database.cc

@@ -325,6 +325,10 @@ future<> keyspace::populate(sstring ksdir) {
     });
 }
 
+database::database() {
+    keyspaces.emplace("system", db::system_keyspace::make());
+}
+
 future<> database::populate(sstring datadir) {
     return lister::scan_dir(datadir, directory_entry_type::directory, [this, datadir] (directory_entry de) {
         auto& ks_name = de.name;
@@ -343,7 +347,6 @@ future<> database::populate(sstring datadir) {
 
 future<>
 database::init_from_data_directory(sstring datadir) {
-    keyspaces.emplace("system", db::system_keyspace::make());
     return populate(datadir);
 }
 

database.hh

@@ -315,6 +315,7 @@ public:
 
 class database {
 public:
+    database();
     std::unordered_map<sstring, keyspace> keyspaces;
     future<> init_from_data_directory(sstring datadir);
     future<> populate(sstring datadir);