modem-manager: bump to version 1.6.0

MUSL build was fixed in this release.

Fixes:
http://autobuild.buildroot.net/results/fcc/fcce95bd13407535bee336e34288b55142ae0bb5

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/modem-manager/modem-manager.hash

@@ -1,2 +1,2 @@
 # Locally computed:
-sha256  abe6cdd515a774bcba3afdcdb1e504569801e79282ccdf26099f33cbb8731ba2  ModemManager-1.4.14.tar.xz
+sha256  a94f4657a8fa6835e2734fcc6edf20aa8c8d452f62299d7748541021c3eb2445  ModemManager-1.6.0.tar.xz

package/modem-manager/modem-manager.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-MODEM_MANAGER_VERSION = 1.4.14
+MODEM_MANAGER_VERSION = 1.6.0
 MODEM_MANAGER_SOURCE = ModemManager-$(MODEM_MANAGER_VERSION).tar.xz
 MODEM_MANAGER_SITE = http://www.freedesktop.org/software/ModemManager
 MODEM_MANAGER_LICENSE = GPLv2+ (programs, plugins), LGPLv2+ (libmm-glib)