BUILDBOT: Switch AmigaOS4 tools build to new packaging target name.

Also, add reminder comment for v1.8.0 release preparations.

config/master.cfg

@@ -1126,7 +1126,7 @@ p_master = {
 	],
 	"env": scumm_env_amigaos4,
 	"disttarget": "amigaos4dist",
-	"disttarget-tools": "aos4dist",
+	"disttarget-tools": "amigaos4dist",
 	"package": [ "Games:ScummVM" ],
 	"package-tools": [
 		"construct_mohawk",
@@ -1147,6 +1147,7 @@ p_master = {
 }
 
 p_stable = copy.deepcopy(p_master)
+# TODO: Remove or change following to "amigaos4dist" when v1.8.0 becomes stable
 p_stable["disttarget"] = "aos4dist"
 
 scumm_platforms_master["amigaos4"] = p_master