[network-manager-applet] c-e: improve error message for non-existing certificate file

[Thomas Haller <thaller src gnome org>]

commit b603844fc50679fc8683227bfa0f3b6c8e77c2c7
Author: Thomas Haller <thaller redhat com>
Date:   Thu Mar 23 12:28:12 2017 +0100

    c-e: improve error message for non-existing certificate file
    
    When the connection references a certifiate file that does not exist,
    the GUI's file picker button shows an "(None)", however the "Save"
    button is disable with message:
    
      "Invalid setting Wi-Fi Security: invalid EAP-PEAP CA certificate: unspecified error validating 
eap-method file"
    
    Slightly improve that by showing instead
    
      "Invalid setting Wi-Fi Security: invalid EAP-PEAP CA certificate: file "..." does not exist"
    
    The solution is not optimal because the GUI shows file "(None)",
    with is some hidden information that makes the connection invalid.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=780423

 src/wireless-security/eap-method.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/wireless-security/eap-method.c b/src/wireless-security/eap-method.c
index b25fbe1..46628d3 100644
--- a/src/wireless-security/eap-method.c
+++ b/src/wireless-security/eap-method.c
@@ -236,6 +236,7 @@ eap_method_validate_filepicker (GtkBuilder *builder,
 
        if (!g_file_test (filename, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR)) {
                success = FALSE;
+               g_set_error (error, NMA_ERROR, NMA_ERROR_GENERIC, _("file \"%s\" does not exist"), filename);
                goto out;
        }