Please binNMU libssh2 in clean build environment

[Mikhail Gusarov <dottedmag@debian.org>]

Hello.

libssh2 1.5.0-2 i386 was built in an environment with GZIP environment
variable leaked from outside
(#781603) which made changelog.gz file to mismatch the one in amd64
package. Please binNMU it to
restore multiarch coinstallability.

  nmu libssh2_1.5.0-2 . i386 . -m 'Rebuild in clean environment (Closes:
  #781603, #781756)'

Thank you.