Merge branch '4.4' into 5.1

* 4.4:
  [appveyor] fix checking for the .x branch
  Remove "branch-alias", populate "version"

Author: nicolas-grekas

composer.json

@@ -51,9 +51,5 @@
         ]
     },
     "minimum-stability": "dev",
-    "extra": {
-        "branch-alias": {
-            "dev-master": "5.1-dev"
-        }
-    }
+    "version": "5.1-dev"
 }