cabinet: Constify some variables (1 of 3)

[Andrew Talbot]

Changelog:
    cabinet: Constify some variables.

diff -urN a/dlls/cabinet/cabinet_main.c b/dlls/cabinet/cabinet_main.c
--- a/dlls/cabinet/cabinet_main.c	2006-10-20 18:07:56.000000000 +0100
+++ b/dlls/cabinet/cabinet_main.c	2007-03-14 23:06:00.000000000 +0000
@@ -154,7 +154,7 @@
     return SetFilePointer(handle, dist, NULL, seektype);
 }
 
-static void fill_file_node(struct ExtractFileList *pNode, LPSTR szFilename)
+static void fill_file_node(struct ExtractFileList *pNode, LPCSTR szFilename)
 {
     pNode->next = NULL;
     pNode->flag = FALSE;
@@ -163,7 +163,7 @@
     lstrcpyA(pNode->filename, szFilename);
 }
 
-static BOOL file_in_list(struct ExtractFileList *pNode, LPSTR szFilename)
+static BOOL file_in_list(const struct ExtractFileList *pNode, LPCSTR szFilename)
 {
     while (pNode)
     {