Fix #1145: sanitize model name in PHP client

Author: xhh

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java

@@ -330,6 +330,8 @@ public String toParamName(String name) {
 
     @Override
     public String toModelName(String name) {
+        name = sanitizeName(name);
+
         // model name cannot use reserved keyword
         if (reservedWords.contains(name)) {
             escapeReservedWord(name); // e.g. return => _return