cli_ure: climaker should open keyfile read-only

This should fix build failures due to file locking preventing concurrent
access to cli_ure/source/cliuno.snk.

Change-Id: Iefd16ed83a01523b3612844c2f777516dc4e44c6
(cherry picked from commit 01518d3a)
Reviewed-on: https://gerrit.libreoffice.org/19483Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
(cherry picked from commit d0d03f22)

cli_ure/source/climaker/climaker_app.cxx

@@ -462,7 +462,8 @@ SAL_IMPLEMENT_MAIN()
             ::System::String ^ sKeyFile = ustring_to_String(keyfile);
             try {
                 System::IO::FileStream^ fs = gcnew System::IO::FileStream(
-                    sKeyFile, System::IO::FileMode::Open);
+                    sKeyFile, System::IO::FileMode::Open,
+                    System::IO::FileAccess::Read, System::IO::FileShare::Read);
                 kp = gcnew StrongNameKeyPair(fs);
                 fs->Close();
             }