The current distribution of
apt-get is not patched with latest version Qt,
hence there are many issues in wkhtmltopdf.
To solve this, we can manually install updated
wkhtmltopdf from official website itself.
First, install from apt-get itself,
(sudo) apt-get install wkhtmltopdf
Next, download the updated file from http://wkhtmltopdf.org/downloads.html
After extracking it, copy the binary from downloaded file, to the
(sudo) cp /bin/wkhtmltopdf /usr/bin/