[SECURITY] [DLA 211-1] curl security update

Package : curl
Version : 7.21.0-2.1+squeeze12
CVE ID : CVE-2015-3143 CVE-2015-3148

Several vulnerabilities were discovered in cURL, an URL transfer library:

CVE-2015-3143

NTLM-authenticated connections could be wrongly reused for requests
without any credentials set, leading to HTTP requests being sent
over the connection authenticated as a different user. This is
similar to the issue fixed in DSA-2849-1.

CVE-2015-3148

When doing HTTP requests using the Negotiate authentication method
along with NTLM, the connection used would not be marked as
authenticated, making it possible to reuse it and send requests for
one user over the connection authenticated as a different user.