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

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1317 matching lines @@
             'editing/commands/CompositeEditCommand.h',
             'editing/commands/CreateLinkCommand.cpp',
             'editing/commands/CreateLinkCommand.h',
             'editing/commands/DeleteFromTextNodeCommand.cpp',
             'editing/commands/DeleteFromTextNodeCommand.h',
             'editing/commands/DeleteSelectionCommand.cpp',
             'editing/commands/DeleteSelectionCommand.h',
             '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',
             'editing/commands/IndentOutdentCommand.h',
             'editing/commands/InsertIntoTextNodeCommand.cpp',
             'editing/commands/InsertIntoTextNodeCommand.h',
             'editing/commands/InsertLineBreakCommand.cpp',
             'editing/commands/InsertLineBreakCommand.h',
             'editing/commands/InsertListCommand.cpp',
             'editing/commands/InsertListCommand.h',
@@ skipping 2508 matching lines @@
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }