packer/getter: don't report other os/arch as errs

Whenever a Github release exposes an entry for another OS/arch
combination, this gets registered as an error, which in the event no
binary is compatible with the host's OS/arch, gets reported at the end
of the getter process.

While this is sound in theory, in practice we get the list of all the
combinations that don't match the host's, which is not something a
Packer user can act on, and might therefore be more confusing than
helping to solve the issue.

Therefore we opt in this commit to stop registering those cases as real
errors, and only log them as an INFO statement.

packer/plugin-getter/plugins.go

@@ -680,9 +680,7 @@ func (pr *Requirement) InstallLatest(opts InstallOptions) (*Installation, error)
 						continue
 					}
 					if err := entry.validate("v"+version.String(), opts.BinaryInstallationOptions); err != nil {
-						err := fmt.Errorf("ignoring invalid remote binary %s: %s", entry.Filename, err)
-						errs = multierror.Append(errs, err)
-						log.Printf("[TRACE] %s", err)
+						log.Printf("[INFO] ignoring invalid remote binary %s: %s", entry.Filename, err)
 						continue
 					}