Fix package dependency on debian jessie

I removed the unnecessary dependency to libjpeg8 and libpcre3 in Build-Depends field (dev packages are already listed) and I added dependency to libjpeg* in Depends field.
I also added an alternative build dependency to libgcrypt20-dev (libgcrypt11-dev may be missing because this is a transitional dummy package for the migration to libgcrypt20-dev).
Now I can build and install ZM on jessie but there is still some work to get it running (discussion https://github.com/ZoneMinder/ZoneMinder/pull/592).