If I right click on any folder or file and then select "Properties" Thunar will
crash.

Reproducible: Always
Steps to Reproduce:
1. Right Click on any folder or file
2. Select Properties from the menu
3. Thunar will crash

Actual Results:  
Thunar crashes


My user in /etc/passwd does not have a real name entry which I believe is
causing the crash. In thunar-permissions-model.c, line 438,
thunar_vfs_user_get_real_name returns NULL and this is immediately followed by a
string compare which results in the crash.  As for real_name having a null
value, this seems to be a result of pw->pw_gecos containing what appears to be
invalid data in function thunar_vfs_user_load.  

Please see the attached patch.