libimobiledevice: update to 2020-02-19

Added config directory patch.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
(cherry picked from commit 7a1435e5f4)

libs/libimobiledevice/patches/020-config.patch

@@ -0,0 +1,11 @@
+--- a/common/userpref.c
++++ b/common/userpref.c
+@@ -159,7 +159,7 @@ const char *userpref_get_config_dir()
+ #ifdef __APPLE__
+ 	base_config_dir = strdup("/var/db");
+ #else
+-	base_config_dir = strdup("/var/lib");
++	base_config_dir = strdup("/etc");
+ #endif
+ #endif
+ 	__config_dir = string_concat(base_config_dir, DIR_SEP_S, USERPREF_CONFIG_DIR, NULL);