Fix test: add client certificate files to AC_CONFIG_FILES

The client_cert.pem and client_key.pem files need to be copied to the
build directory during configure, similar to how other test certificate
files are handled.

Author: etr

configure.ac

@@ -300,6 +300,8 @@ AC_CONFIG_FILES([test/test_content_large:test/test_content_large])
 AC_CONFIG_FILES([test/cert.pem:test/cert.pem])
 AC_CONFIG_FILES([test/key.pem:test/key.pem])
 AC_CONFIG_FILES([test/test_root_ca.pem:test/test_root_ca.pem])
+AC_CONFIG_FILES([test/client_cert.pem:test/client_cert.pem])
+AC_CONFIG_FILES([test/client_key.pem:test/client_key.pem])
 AC_CONFIG_FILES([test/libhttpserver.supp:test/libhttpserver.supp])
 AC_CONFIG_FILES([examples/cert.pem:examples/cert.pem])
 AC_CONFIG_FILES([examples/key.pem:examples/key.pem])