cmdutil.jsonchangeset: properly compute added and removed files

jsonchangeset._show() was computing the reverse status of the current
changeset. As a result, added files were showing up as removed and
removed files were showing up as adds.

There were existing tests for this code and they were flat out wrong.

mercurial/cmdutil.py

@@ -1072,7 +1072,7 b' class jsonchangeset(changeset_printer):'
                           ", ".join('"%s": "%s"' % (j(k), j(v))
                                     for k, v in ctx.extra().items()))
 
-            files = ctx.status(ctx.p1())
+            files = ctx.p1().status(ctx)
             self.ui.write(',\n  "modified": [%s]' %
                           ", ".join('"%s"' % j(f) for f in files[0]))
             self.ui.write(',\n  "added": [%s]' %

tests/test-command-template.t

@@ -696,8 +696,8 b' Test JSON style:'
     "manifest": "94961b75a2da554b4df6fb599e5bfc7d48de0c64",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": ["second"],
-    "removed": ["fourth", "third"]
+    "added": ["fourth", "third"],
+    "removed": ["second"]
    },
    {
     "rev": 7,
@@ -713,8 +713,8 b' Test JSON style:'
     "manifest": "f2dbc354b94e5ec0b4f10680ee0cee816101d0bf",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": [],
-    "removed": ["second"]
+    "added": ["second"],
+    "removed": []
    },
    {
     "rev": 6,
@@ -747,8 +747,8 b' Test JSON style:'
     "manifest": "4dc3def4f9b4c6e8de820f6ee74737f91e96a216",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": [],
-    "removed": ["d"]
+    "added": ["d"],
+    "removed": []
    },
    {
     "rev": 4,
@@ -798,8 +798,8 b' Test JSON style:'
     "manifest": "6e0e82995c35d0d57a52aca8da4e56139e06b4b1",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": [],
-    "removed": ["c"]
+    "added": ["c"],
+    "removed": []
    },
    {
     "rev": 1,
@@ -815,8 +815,8 b' Test JSON style:'
     "manifest": "4e8d705b1e53e3f9375e0e60dc7b525d8211fe55",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": [],
-    "removed": ["b"]
+    "added": ["b"],
+    "removed": []
    },
    {
     "rev": 0,
@@ -832,8 +832,8 b' Test JSON style:'
     "manifest": "a0c8bcbbb45c63b90b70ad007bf38961f64f2af0",
     "extra": {"branch": "default"},
     "modified": [],
-    "added": [],
-    "removed": ["a"]
+    "added": ["a"],
+    "removed": []
    }
   ]