The error reporting assures an exception is thrown if
setKeyStoreFile(null) is called without a prior call to
setKeyStoreLocation(String directory).
Also, fix TrustManagerFactoryTest indentation.
Instead, have K9.onCreate initialize the location of the key
store file (similar to what is done with
BinaryTempFileBody.setTempDirectory).
Also, LocalKeyStore.getInstance has been changed so that it
no longer needs to be synchronized.