Update AzureRMVMExtensionImage cmdlet name to AzureRmVMExtensionImage

Author: hyonholee

src/ResourceManager/Compute/Commands.Compute/Common/ConstantStringTypes.cs

@@ -79,7 +79,7 @@ public static class ProfileNouns
         public const string VirtualMachineCustomScriptExtension = "AzureRmVMCustomScriptExtension";
         public const string VirtualMachineAccessExtension = "AzureRmVMAccessExtension";
         public const string VirtualMachineDiagnosticsExtension = "AzureRmVMDiagnosticsExtension";
-        public const string VirtualMachineExtensionImage = "AzureRmVmExtensionImage";
+        public const string VirtualMachineExtensionImage = "AzureRmVMExtensionImage";
         public const string VirtualMachineExtensionImageVersion = "AzureRmVMExtensionImageVersion";
         public const string VirtualMachineExtensionImageType = "AzureRmVMExtensionImageType";