remove hack for linode not filtering avail.linodeplans by planid
rescue with correct Linode::NotFound namespace
fix signature to properly escape

ensures we properly escape the + sign.
Update signaturev4.rb

don't use deprecated URI.escape
Merge pull request #3141 from displague/linode_plans_filter_by_id

Linode plans filter by planid, remove hack
Merge pull request #3144 from backupify/master

S3 invalid signature generation