libsepol: declare file local variable static

Clang issues:

    module_to_cil.c:65:7: warning: no previous extern declaration for non-static variable 'out_file' [-Wmissing-variable-declarations]
    FILE *out_file;
          ^

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>

libsepol/src/module_to_cil.c

@@ -62,7 +62,7 @@
 #  define UNUSED(x) UNUSED_ ## x
 #endif
 
-FILE *out_file;
+static FILE *out_file;
 
 #define STACK_SIZE 16
 #define DEFAULT_LEVEL "systemlow"