Protect various compgen invocations from -* leakage (Debian: #766163)
(testsuite) Add cd in dir without subdirs or CDPATH test case
_pnames: Add -s for producing (possibly) truncated names (RedHat: #744406)

pgrep and pkill actually expect these instead of the full names.
Actually install the lz4 completion
_completion_loader: Protect compgen from -* leakage (Debian: #769399)
gphoto2: Fix split argument handing, and colon treatment in --port args
*: Invoke command to be completed, not its basename
gphoto2: Replace tail with awk
ccache: Add -o/--set-config arg name completion