Minor fixes for default SMB group

This patch contains additional minor fixes which were proposed during
review but were not pushed (accidentaly). Also amends a name of the
default SMB group in a list of protected groups in group.py.

https://fedorahosted.org/freeipa/ticket/3147

install/share/default-smb-group.ldif

@@ -1,7 +1,7 @@
 dn: cn=Default SMB Group,cn=groups,cn=accounts,$SUFFIX
 changetype: add
 cn: Default SMB Group
-description: Fallback group for primary group RID, do not add user to this group
+description: Fallback group for primary group RID, do not add users to this group
 gidnumber: 999
 objectclass: top
 objectclass: ipaobject

ipalib/plugins/group.py

@@ -107,7 +107,7 @@ Example:
    ipa group-add-member ad_admins --groups ad_admins_external
 """)
 
-PROTECTED_GROUPS = (u'admins', u'trust admins', u'default_smb_group')
+PROTECTED_GROUPS = (u'admins', u'trust admins', u'default smb group')
 
 class group(LDAPObject):
     """

ipaserver/install/adtrustinstance.py

@@ -238,8 +238,8 @@ class ADTRUSTInstance(service.Service):
         try:
             self.admin_conn.getEntry(fb_group_dn, ldap.SCOPE_BASE)
         except errors.NotFound:
-                self.print_msg("Failed to add fallback group.")
-                return
+            self.print_msg("Failed to add fallback group.")
+            return
 
         try:
             mod = [(ldap.MOD_ADD, self.ATTR_FALLBACK_GROUP, fb_group_dn)]