Bug 14152: Re-check required dependencies during upgrade process

Bug 14152: Re-check required dependencies during upgrade process

This code causes the installer to re-check dependencies during the
upgrade process.

Test Plan
---------
1) Log in to staff client
2) Koha Administration -> Global system preferences -> Local
3) Change Version to previous version -- DO NOT HIT SAVE YET!
4) In command line: sudo apt-get purge libpdf-fromhtml-perl
   NOTE: This could be ANY required library. I chose
         PDF::FromHTML, because it has been a thorn in my side.
5) NOW! Hit the 'Save' button.
6) Log in, etc. etc...
   -- Blows up on redirect to log in.
7) In command line, add it back (I had to compile my own so,
   I used sudo dpkg -i /path/to/libpdf-fromhtml-perl...)
8) Apply patch
9) Edit the C4/Installer/PerlDependencies.pm to make
   PDF::FromHTML required. See also bug 14103.
10) Log in to staff client
11) Koha Administration -> Global system preferences -> Local
12) Change Version to previous version -- DO NOT HIT SAVE YET!
13) In command line: sudo apt-get purge libpdf-fromhtml-perl
14) NOW! Hit the 'Save' button.
15) Log in, etc. etc...
16) Once warned you are missing it, add it back at the command line.
17) Click 'Recheck'
    -- Proceeds as expected now.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>