It's ok. I found the solution myself. all I had to do is to enter the
following command lines one after another...
apt-get -f install
Then any package that is unnecessary will be either removed or
After that I re-installed nginx "the new version 1.6.0" to make sure
things are working fine...
so I run this command to see what packages are on:
sudo dpkg -l | grep nginx
since all necessary packages for Nginx are installed, I had to use this
command to remove all at once:
apt-get remove --purge nginx-common
This way all new version 1.6.0 of Nginx are removed!!
I hope this answer is going to be useful for anyone who run into such