[gimp] libgimp: clean up some warnings when building with MSYS 64bit.

[Jehan <jehanp src gnome org>]

commit 796346242911a0e4708bd51c457b0c27cdbac180
Author: Jehan <jehan girinstud io>
Date:   Tue Aug 27 14:58:48 2019 +0200

    libgimp: clean up some warnings when building with MSYS 64bit.
    
    See #3852.
    Fixes:
    > warning: 'n_return_vals' may be used uninitialized in this function
    > warning: 'n_args' may be used uninitialized in this function

 libgimp/gimpprocedure.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/libgimp/gimpprocedure.c b/libgimp/gimpprocedure.c
index 20a3b825a5..fe5e3f6583 100644
--- a/libgimp/gimpprocedure.c
+++ b/libgimp/gimpprocedure.c
@@ -294,8 +294,8 @@ gimp_procedure_real_install (GimpProcedure *procedure)
 {
   GParamSpec   **args;
   GParamSpec   **return_vals;
-  gint           n_args;
-  gint           n_return_vals;
+  gint           n_args        = 0;
+  gint           n_return_vals = 0;
   GList         *list;
   GimpPlugIn    *plug_in;
   GPProcInstall  proc_install;