LP#1563531: add libpcre3/libpcre3-dev deps for Jessie

LP#1563531: add libpcre3/libpcre3-dev deps for Jessie

This patch adds libpcre3 and libpcre3-dev to the list
of packages installed when installing Evergreen on Debian
Jessie. Evergreen's direct dependency on libpcre3 is new in 2.10
(see bug 1468422); it happens that libpcre3 and libpcre3-dev
are installed on Wheezy by virtue of a different dependency
chain.

To test
-------
[1] On a fresh Debian Jessie netinstall, follow the OpenSRF
    and Evergreen installation instructions. Verify that with
    this patch in place, Evergreen's "configure" step succeeds.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>