Bug 10925: fix LDAP auth failing if DEBUG is enabled

Bug 10925: fix LDAP auth failing if DEBUG is enabled

To reproduce:
1/ Edit your apache virtual host and set the DEBUG environment variable
(SetEnv DEBUG 1).
2/ Try to login with an ldap user
3/ You will be redirected to the 500 error page.
The Koha logs contains:
malformed header from script. Bad header=------------------------------: mainpage.pl

The hashdump routine directly prints to STDOUT (!) and breaks the
headers.
It appears Net::LDAP::?->dump does the same thing.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Maybe we can kill C4::Utils after getting rid of this

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 561107bb5b348eaa14054e3470f39ff9cf080d22)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>