Remove double whitespace in help string

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

htools/Ganeti/HTools/CLI.hs

@@ -199,7 +199,7 @@ oEvacMode = Option "E" ["evac-mode"]
 oExInst :: OptType
 oExInst = Option "" ["exclude-instances"]
           (ReqArg (\ f opts -> Ok opts { optExInst = sepSplit ',' f }) "INSTS")
-          "exclude given instances  from any moves"
+          "exclude given instances from any moves"
 
 oExTags :: OptType
 oExTags = Option "" ["exclusion-tags"]