Get rid of an extra file core/editing/commands/EditorCommand.h from core.gypi

This patch gets rid of an extra file "core/editing/commands/EditorCommand.h"
from "core.gypi" added by http://crrev.com/1294543005.

TBR=brucedawson@chromium.org
BUG=509527
TEST=n/a; no behavior changes
NOTRY=true

Review URL: https://codereview.chromium.org/1312003002

git-svn-id: svn://svn.chromium.org/blink/trunk@201083 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/core.gypi

@@ -1335,7 +1335,6 @@
             'editing/commands/EditCommand.cpp',
             'editing/commands/EditCommand.h',
             'editing/commands/EditorCommand.cpp',
-            'editing/commands/EditorCommand.h',
             'editing/commands/FormatBlockCommand.cpp',
             'editing/commands/FormatBlockCommand.h',
             'editing/commands/IndentOutdentCommand.cpp',