[gimp] app: make user_install_dir_copy() recursive.

[Jehan Pagès <jehanp src gnome org>]

commit cf6744178204e07b1534a30de728d40f083a2d66
Author: Jehan <jehan girinstud io>
Date:   Tue Dec 26 16:44:33 2017 +0100

    app: make user_install_dir_copy() recursive.
    
    In particular, I noticed that some data can be on 2 levels (or more?).
    For instance gimpressionist presets were not migrated from 2.8 to 2.9
    because of this.

 app/core/gimp-user-install.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimp-user-install.c b/app/core/gimp-user-install.c
index 1aa27f4..240fb65 100644
--- a/app/core/gimp-user-install.c
+++ b/app/core/gimp-user-install.c
@@ -664,6 +664,10 @@ user_install_dir_copy (GimpUserInstall *install,
               goto error;
             }
         }
+      else
+        {
+          user_install_dir_copy (install, name, dirname);
+        }
 
       g_free (name);
     }