[1.7.x] Added release date for 1.7.5 release.
[1.7.x] Added release date for 1.7.5 release.

Backport of aca73737da8ba173ad9435b1e9e1fe5d8516f3b3 from master

jyotsna1820/django,jyotsna1820/django,oscaro/django,oscaro/django,jyotsna1820/django,oscaro/django,oscaro/django,jyotsna1820/django