Prevent account's activate/deactivate methods to run at the same time

Ignore-this: 3f8fe7ad62a64494181f153821da9fda

darcs-hash:20121112133638-b22ec-d59e9ae9a4df2357a27a39084c3eb15372b8164f
Removed unnecessary assignment

Ignore-this: ddcf8928aee6d32bcf0170ad5144da89

darcs-hash:20121112152929-56b4d-849d159bc79ab85686130e4e30b6c55a9fde810d