relicense libtasn1 to LGPLv3+

[Simon Josefsson]

We are considering re-licensing Libtasn1 to LGPLv3+ and I wanted to hear
if there are any strong reasons against that.

What could be a problem is if there is a significant reverse dependency
with a license conflict.  I went through each reverse dependencies for
libtasn1 in debian sid except gnutls as an indication of this:

  libshishi0: GPLv3+
  libimobiledevice2: LGPL2+
  libimobiledevice-utils: LGPLv2+
  hardinfo: GPLv2 [1]
  csync2: GPLv2+

Thus I think we are in good shape and could make the re-licensing for
the next release.

[1] hardinfo is GPLv2 only but I can't find any traces of references to
libtasn1 or gnutls in the source code, so I suspect the dependency on
libtasn1 is incorrect.

/Simon