mq: make qnew patch format consistent with qrefresh (issue1457)

hgext/mq.py

@@ -756,7 +756,7 b' class queue:'
                     self.series_dirty = 1
                     self.applied_dirty = 1
                     if msg:
-                        msg = msg + "\n"
+                        msg = msg + "\n\n"
                         p.write(msg)
                     if commitfiles:
                         diffopts = self.diffopts()

tests/test-mq-header-date.out

@@ -48,6 +48,7 b' Now at: 1.patch'
 # Date 6 0
 
 Three
+
 1: Three - test - 6.00
 0: [mq]: 1.patch - test - 4.00
 ==== qref

tests/test-mq-header-from.out

@@ -46,6 +46,7 b' 0: [mq]: 1.patch - mary'
 From: test
 
 Three
+
 2: Three - test
 1: [mq]: 2.patch - jane
 0: [mq]: 1.patch - mary

tests/test-mq-qnew.out

@@ -15,6 +15,7 b' A test.patch'
 abort: missing: No such file or directory
 % qnew -m
 foo bar
+
 % qnew twice
 abort: patch "first.patch" already exists
 abort: patch "first.patch" already exists