Avoid a crash when attempting to change password

In some cases we could keep stack garbage in a local pointer
variable until the cleanup at the end of the function wherein
krb5_free_context() would choke on the invalid non-NULL value.
Initialize to zero to avoid the issue (should be written as NULL
but stick to the prevailing style).

https://github.com/krb5/krb5/commit/023aac4a5d682ffeacc5121deaa771e08a5c9013
Author: Benjamin Kaduk <kaduk@mit.edu>
Committer: Ben Kaduk <kaduk@mit.edu>
Commit: 023aac4a5d682ffeacc5121deaa771e08a5c9013
Branch: master
 src/windows/leash/LeashView.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)