[master] Fixed dhcpsrv/testutils compilation issue.

The mysql_generic_backend_unittest.cc is conditionally compiled when
MySQL is available.

src/lib/dhcpsrv/testutils/Makefile.am

@@ -19,11 +19,14 @@ libdhcpsrvtest_la_SOURCES += memory_host_data_source.cc memory_host_data_source.
 libdhcpsrvtest_la_SOURCES += generic_backend_unittest.cc generic_backend_unittest.h
 libdhcpsrvtest_la_SOURCES += generic_host_data_source_unittest.cc generic_host_data_source_unittest.h
 libdhcpsrvtest_la_SOURCES += lease_file_io.cc lease_file_io.h
-libdhcpsrvtest_la_SOURCES += mysql_generic_backend_unittest.cc mysql_generic_backend_unittest.h
 libdhcpsrvtest_la_SOURCES += test_config_backend.h
 libdhcpsrvtest_la_SOURCES += test_config_backend_dhcp4.cc test_config_backend_dhcp4.h
 libdhcpsrvtest_la_SOURCES += test_config_backend_dhcp6.cc test_config_backend_dhcp6.h
 
+if HAVE_MYSQL
+libdhcpsrvtest_la_SOURCES += mysql_generic_backend_unittest.cc mysql_generic_backend_unittest.h
+endif
+
 libdhcpsrvtest_la_CXXFLAGS = $(AM_CXXFLAGS)
 libdhcpsrvtest_la_CPPFLAGS = $(AM_CPPFLAGS) $(GTEST_INCLUDES)