7712: Use full path for file existence check

gramps/gui/editors/editmedia.py

@@ -295,7 +295,8 @@ class EditMedia(EditPrimary):
             return
 
         path = conv_to_unicode(self.file_path.get_text())
-        if os.path.isfile(path):
+        full_path = media_path_full(self.db, path)
+        if os.path.isfile(full_path):
             self.determine_mime()
         else:                                                              
             msg1 = _("There is no media matching the current path value!") 
@@ -307,7 +308,7 @@ class EditMedia(EditPrimary):
             self.ok_button.set_sensitive(True)                             
             return                                                         
 
-        self.obj.set_path(conv_to_unicode(path))
+        self.obj.set_path(path)
 
         with DbTxn('', self.db) as trans:
             if not self.obj.get_handle():