With the shell in nounset mode, an error is emitted on referencing
`schemadir` as it is not initialized in all code paths.
Initialize to an empty string to fix.
Signed-off-by: Ville Skyttä <ville.skytta@iki.fi>
The bash-completion code nowadays expects completion files to
be installed in /usr/share/bash-completion/completions, and
expects them to be named like the command they are completing
for.
https://bugzilla.gnome.org/show_bug.cgi?id=677782
