THRIFT-4969: PHP test doesn't check the code generation with php:classmap

Client: php

This closes #1889.
diff --git a/test/php/Makefile.am b/test/php/Makefile.am
index 52765ee..9e13aff 100755
--- a/test/php/Makefile.am
+++ b/test/php/Makefile.am
@@ -21,7 +21,7 @@
 	$(THRIFT) --gen php ../ThriftTest.thrift
 	$(THRIFT) --gen php:inlined ../ThriftTest.thrift
 	$(MKDIR_P) gen-php-classmap
-	$(THRIFT) -out gen-php-classmap --gen php ../ThriftTest.thrift
+	$(THRIFT) -out gen-php-classmap --gen php:classmap ../ThriftTest.thrift
 
 php_ext_dir:
 	mkdir -p php_ext_dir