SDK: change proguard.config for Windows.

Change the default to use / dir-separators even
for the Windows template. The / will be correctly
replaced by \\ by both Ant and our ExportHelper,
ensuring a relative path works on all platforms.

SDK bug: 28860

(This does not solve the path-separator issue with
; vs : on Windows. That will be addressed later.)

Change-Id: Iee3ae9c58aa606aee7943c4e20643164bbf7344b
1 file changed