ShellPkg: Move SHELL_FREE_NON_NULL from ShellBase.h to ShellLib.h

The more proper place for macro SHELL_FREE_NON_NULL is ShellLib.h
instead of ShellBase.h.

Modify Compress.c to resolve build failure due to this change.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>

ShellPkg/Include/Library/ShellLib.h

@@ -1,7 +1,7 @@
 /** @file
   Provides interface to shell functionality for shell commands and applications.
 
-  Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -24,6 +24,14 @@
 #include <Protocol/EfiShell.h>
 #include <Protocol/EfiShellParameters.h>
 
+#define SHELL_FREE_NON_NULL(Pointer)  \
+  do {                                \
+    if ((Pointer) != NULL) {          \
+      FreePool((Pointer));            \
+      (Pointer) = NULL;               \
+    }                                 \
+  } while(FALSE)
+
 // (20 * (6+5+2))+1) unicode characters from EFI FAT spec (doubled for bytes)
 #define MAX_FILE_NAME_LEN 512