pkg/client: Fix ignored files matching.

Because of Go's rules regaring closures (function literals) and bound
variables, in the case in which there were multiple patterns in the
ignoredFiles configuration variable, the entire slice (vector) of
registered matching functions was being called with the
last-configured ignoredFiles pattern as the first variable. This meant
that ignoredFiles did not work if it contained more than one pattern
and in certain circumstances, such a configuration would lead to a
crash.

Change-Id: I0b991aa74d079d4ce27fc0ba373e2ee2cf9eb772
buildbot: add some context to error

Change-Id: Ia0733909ffd4d9e9451ac663cb7ece799169ab7c
Merge "buildbot: add some context to error"
Handle Photoshop images better.

We still can't find their width/height or thumbnail the, but at least
we don't wedge the UI now.

Fixes camlistore.org/issue/389

Change-Id: I8af6cefa5d84e7f6e26f3920e4dd6e1d5eb8b192