[2825] Removed "mysql" directory prefix from #include statements.

The include path for MySQL includes is accurately set by mysql_config.

src/lib/dhcpsrv/mysql_lease_mgr.cc

@@ -21,7 +21,7 @@
 #include <dhcpsrv/mysql_lease_mgr.h>
 
 #include <boost/static_assert.hpp>
-#include <mysql/mysqld_error.h>
+#include <mysqld_error.h>
 
 #include <iostream>
 #include <iomanip>

src/lib/dhcpsrv/mysql_lease_mgr.h

@@ -20,7 +20,7 @@
 
 #include <boost/scoped_ptr.hpp>
 #include <boost/utility.hpp>
-#include <mysql/mysql.h>
+#include <mysql.h>
 
 #include <time.h>