debian: fix installing pdfs for -doc package

Don't comment out the pdf glob, it works as intended when building the
package on OBS. I had disabled it, because with dpkg-buildpackage,
override_dh_auto_configure from debian/ruls gets ignored, leading to
--enable-manuals missing in ./configure, and to the pdf file not being
present. But apparently, dpkg-buildpackage just always ignores this,
it's the same with other Osmocom repositories.

Related: OS#4992
Change-Id: I67c71af1406516e1262792b0d7566b3a9470e37f
diff --git a/debian/osmo-gbproxy-doc.install b/debian/osmo-gbproxy-doc.install
index d934088..cb5b384 100644
--- a/debian/osmo-gbproxy-doc.install
+++ b/debian/osmo-gbproxy-doc.install
@@ -1,2 +1 @@
-# FIXME: debian package doesn't generate manuals yet, see OS#4992
-# usr/share/doc/osmo-gbproxy-doc/*.pdf
+usr/share/doc/osmo-gbproxy-doc/*.pdf