Remove align's Doxygen reference.xml

doc/Jamfile.v2

@@ -84,7 +84,6 @@ boostbook doc
     <dependency>../libs/lockfree/doc//lockfree
     <dependency>../libs/atomic/doc//atomic
     <dependency>../libs/type_erasure/doc//type_erasure
-    <dependency>../libs/align/doc//reference.xml
     <dependency>../libs/align/doc//align
     <dependency>../libs/type_index/doc//type_index