base: include types.hh in base/stats/mysql.hh

Due to certain changes made via changeset 8229, the compilation was failing
in certain cases. The compiler pointed to base/stats/mysql.hh for not naming
a certain types like uint64_t. To rectify this, base/types.hh is being
included in base/stats/mysql.hh.

src/base/stats/mysql.hh

@@ -37,6 +37,7 @@
 #include <string>
 
 #include "base/stats/output.hh"
+#include "base/types.hh"
 #include "config/use_mysql.hh"
 
 namespace MySQL { class Connection; }