ci: disable frames in lcov HTML coverage report

Change-Id: Ie7ecce199aefc37b95d721f1032ac69ebe3f8338

.jenkins.d/00-deps.sh

@@ -30,7 +30,7 @@ elif has Ubuntu $NODE_LABELS; then
                              libpcap-dev
 
     if [[ $JOB_NAME == *"code-coverage" ]]; then
-        sudo apt-get -qy install gcovr lcov libgd-perl
+        sudo apt-get -qy install gcovr lcov
     fi
 
 elif has CentOS-8 $NODE_LABELS; then

.jenkins.d/30-coverage.sh

@@ -23,7 +23,6 @@ if [[ $JOB_NAME == *"code-coverage" ]]; then
 
     genhtml --branch-coverage \
             --demangle-cpp \
-            --frames \
             --legend \
             --output-directory build/coverage \
             --title "ndn-tools unit tests" \