Add FBConditionalLog statement to better describe system authorizatio…

…n (ios6) failures that may be caused by misconfiguration.

Summary:
Add FBConditionalLog statement to better describe system authorization (ios6)
failures that may be caused by misconfiguration.

This handles the code = 7 case, where error looks like

{NSLocalizedDescription=The Facebook server could not fulfill this access
request: remote_app_id does not match stored id },  code:7

Test Plan:
Changed bundle identifier in scrumptious to something bogus. Tried to log on
and verified log message in console.
Verified no logging when bundle identifier is correct.

Revert Plan:

Reviewers: jacl

Reviewed By: jacl

Differential Revision: https://phabricator.fb.com/D589249

src/FBSession.m

@@ -1020,6 +1020,13 @@ - (void)authorizeUsingSystemAccountStore:(ACAccountStore*)accountStore
     [accountStore requestAccessToAccountsWithType:accountType
                                           options:options
                                        completion:^(BOOL granted, NSError *error) {
+                                           FBConditionalLog(granted || error.code != ACErrorPermissionDenied ||
+                                                            [error.description rangeOfString:
+                                                                @"remote_app_id does not match stored id"].location == NSNotFound,
+                                                            @"System authorization failed:'%@'. This may be caused by a mismatch between"
+                                                            @" the bundle identifier and your app configuration on the server"
+                                                            @" at developers.facebook.com/apps.",
+                                                            error.localizedDescription);
 
                                            // this means the user has not signed-on to Facebook via the OS
                                            BOOL isUntosedDevice = (!granted && error.code == ACErrorAccountNotFound);