package/tvheadend: Fix inclusion of dtv-scan-tables files

--enable-dvbscan forces downloading the tables from upstream when the
files are not already present in data/dvb-scan/, see support/getmuxlist.

By moving the copy command for the dvb-scan files before tvheadend configure
the getmuxlist script, called by tvheadend configure, will recognize the
existing directory, quote: "# Note: will not update existing set (if not .git)"

To verify the bundled contents have a look at build.linux/bundle.d.
Also fix a comment typo.

Fixes
http://autobuild.buildroot.net/results/25f/25fc657dbc37228483eeefb3618be9df2ee13832/
http://autobuild.buildroot.net/results/37a/37abb5d2ec62ac59897d019e6ca85c8eb0e69786/
http://autobuild.buildroot.net/results/e86/e860e501f904d94bbab6a765aad4d19947135513/
http://autobuild.buildroot.net/results/a55/a55ab4fc34bebda14236d6a0efe893aa75374ed2/



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>