swupdate.inc: Remove spurious character

The backport of 83739ad60931 ("swupdate: introduce swupdate-ipc to factorize packages")
to dunfell and hardknott introduced some spurious characters that break
the build.

Remove them.

Reported-by: Enrique Robledo Arnuncio <era@tegulan.com>
Signed-off-by: Fabio Estevam <festevam@gmail.com>

recipes-support/swupdate/swupdate.inc

@@ -47,8 +47,8 @@ wwwdir ?= "/www"
 
 # tools is now an empty meta package for backward compatibility
 ALLOW_EMPTY_${PN}-tools = "1"
-+ALLOW_EMPTY_${PN}-tools-hawkbit = "1"
-+ALLOW_EMPTY_${PN}-tools-ipc = "1"
+ALLOW_EMPTY_${PN}-tools-hawkbit = "1"
+ALLOW_EMPTY_${PN}-tools-ipc = "1"
 
 FILES_${PN}-client = "${bindir}/swupdate-client"
 FILES_${PN}-lua += "${libdir}/lua/"