ci: improve lcov HTML output

In particular, demangle C++ symbols in the function coverage view.

Change-Id: I882a88fda77c468e26b935ad6088b4254e875151
diff --git a/.jenkins.d/00-deps.sh b/.jenkins.d/00-deps.sh
index 4a4db28..6146177 100755
--- a/.jenkins.d/00-deps.sh
+++ b/.jenkins.d/00-deps.sh
@@ -18,4 +18,9 @@
     sudo apt-get -qq install build-essential pkg-config libboost-all-dev \
                              libcrypto++-dev libsqlite3-dev libssl-dev \
                              libpcap-dev
+
+    if [[ $JOB_NAME == *"code-coverage" ]]; then
+        sudo apt-get -qq install lcov libgd-perl python-setuptools
+        sudo easy_install --upgrade gcovr
+    fi
 fi