Don't use user/password cache from the login page

The idea is to always use memcached for credentials to avoid hitting
the authentication backend on every click but to check with the auth backend
for every login requests.

This should fix #2169

While there, fix whitespace (killtab)

SoObjects/SOGo/SOGoUserManager.h

@@ -82,11 +82,19 @@
 - (NSString *) getLoginForDN: (NSString *) theDN;
 
 - (BOOL) checkLogin: (NSString *) _login
-	   password: (NSString *) _pwd
+           password: (NSString *) _pwd
              domain: (NSString **) _domain
-	       perr: (SOGoPasswordPolicyError *) _perr
-	     expire: (int *) _expire
-	      grace: (int *) _grace;
+               perr: (SOGoPasswordPolicyError *) _perr
+             expire: (int *) _expire
+              grace: (int *) _grace;
+
+- (BOOL) checkLogin: (NSString *) _login
+           password: (NSString *) _pwd
+             domain: (NSString **) _domain
+               perr: (SOGoPasswordPolicyError *) _perr
+             expire: (int *) _expire
+              grace: (int *) _grace
+           useCache: (BOOL) _useCache;
 
 - (BOOL) changePasswordForLogin: (NSString *) login
                        inDomain: (NSString *) domain