taskd: remove redundant _SOURCE definition

.tar.gz is the default.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/taskd/taskd.mk

@@ -5,7 +5,6 @@
 ################################################################################
 
 TASKD_VERSION = 1.1.0
-TASKD_SOURCE = taskd-$(TASKD_VERSION).tar.gz
 TASKD_SITE = http://taskwarrior.org/download
 TASKD_LICENSE = MIT
 TASKD_LICENSE_FILES = COPYING LICENSE