Debugger: Robustify disabling of system pretty printers

There seems to be systems producing non-ASCII error messages when
running this in directories with non-ASCII characters. Since we
won't be able to workaround, silence the error to not disturb
further operation.

Change-Id: I527ce10c062273d2f4928f2a8fab79b704de067b
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

share/qtcreator/debugger/gdbbridge.py

@@ -188,7 +188,11 @@ class PlainDumper:
 
 def importPlainDumpers(args):
     if args == "off":
-        gdb.execute("disable pretty-printer .* .*")
+        try:
+            gdb.execute("disable pretty-printer .* .*")
+        except:
+            # Might occur in non-ASCII directories
+            warn("COULD NOT DISABLE PRETTY PRINTERS")
     else:
         theDumper.importPlainDumpers()