swupdate: bump git srcrev

This includes the following changes:

ed18fc2 Revert "systemd generic startup"
7da867e Add Zstd compression support
2e1fcad doc: hawkbit SSL on port 8443 + swupdate
e42eedf doc: drop integer from REST API

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>

recipes-support/swupdate/swupdate_git.bb

@@ -2,5 +2,5 @@ require swupdate.inc
 
 DEFAULT_PREFERENCE = "-1"
 
-SRCREV ?= "045a618a725d0a2fce64161f10101c0004ac5d85"
+SRCREV ?= "e9df70498e604febf6ff9d56ce742522094cebd5"
 PV = "2019.04+git${SRCPV}"