mpr: Declare a variable static

[Andrew Talbot]

Changelog:
    mpr: Declare a variable static.

diff -urN a/dlls/mpr/wnet.c b/dlls/mpr/wnet.c
--- a/dlls/mpr/wnet.c	2006-10-12 21:30:56.000000000 +0100
+++ b/dlls/mpr/wnet.c	2007-01-11 14:07:54.000000000 +0000
@@ -99,7 +99,7 @@
  */
 static DWORD _findProviderIndexW(LPCWSTR lpProvider);
 
-PWNetProviderTable providerTable;
+static PWNetProviderTable providerTable;
 
 /*
  * Global provider table functions