Merge branch '2.7' into 2.8

* 2.7:
  [Validator] phpize default option values
  test for the Validator component to be present
  [DependencyInjection] Fix on-invalid attribute type in xsd
  [FrameworkBundle] Fix PHP form templates on translatable attributes
  [VarDumper] Fix dumping by-ref variadics

Author: nicolas-grekas

Loader/schema/dic/services/services-1.0.xsd

@@ -153,7 +153,7 @@
     <xsd:attribute name="id" type="xsd:string" />
     <xsd:attribute name="key" type="xsd:string" />
     <xsd:attribute name="name" type="xsd:string" />
-    <xsd:attribute name="on-invalid" type="xsd:string" />
+    <xsd:attribute name="on-invalid" type="invalid_sequence" />
     <xsd:attribute name="strict" type="boolean" />
   </xsd:complexType>
 
@@ -166,7 +166,7 @@
     <xsd:attribute name="id" type="xsd:string" />
     <xsd:attribute name="key" type="xsd:string" />
     <xsd:attribute name="index" type="xsd:integer" />
-    <xsd:attribute name="on-invalid" type="xsd:string" />
+    <xsd:attribute name="on-invalid" type="invalid_sequence" />
     <xsd:attribute name="strict" type="boolean" />
   </xsd:complexType>