acme: Fix arithmetic syntax

Thanks to @jow- for pointing out the mistake.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>

net/acme/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=acme
 PKG_VERSION:=2.7.9
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 PKG_LICENSE:=GPLv3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz

net/acme/files/run.sh

@@ -99,7 +99,7 @@ pre_checks()
                         return 1
                     fi
                     debug "Waiting for nginx to stop..."
-                    tries=$tries+1
+                    tries=$((tries + 1))
                     sleep 1
                 done
             ;;