Better naming & cleanup

Signed-off-by: Jean-Laurent de Morlhon <jeanlaurent@morlhon.net>

drivers/amazonec2/amazonec2.go

@@ -575,7 +575,6 @@ func (d *Driver) GetState() (state.State, error) {
 	}
 }
 
-// GetSSHHostname -
 func (d *Driver) GetSSHHostname() (string, error) {
 	// TODO: use @nathanleclaire retry func here (ehazlett)
 	return d.GetIP()

drivers/amazonec2/region.go

@@ -4,14 +4,6 @@ import (
 	"errors"
 )
 
-var (
-	errInvalidRegion  = errors.New("invalid region specified")
-	errNoVpcs         = errors.New("No VPCs found in region")
-	errMachineFailure = errors.New("Machine failed to start")
-	errNoIP           = errors.New("No IP Address associated with the instance")
-	errComplete       = errors.New("Complete")
-)
-
 type region struct {
 	AmiId string
 }
@@ -49,5 +41,5 @@ func validateAwsRegion(region string) (string, error) {
 		}
 	}
 
-	return "", errInvalidRegion
+	return "", errors.New("invalid region specified")
 }