Fix problems in the pmchart Samples / Visible History dialog
Fix problems in the pmchart Samples / Visible History dialog

There are two problems with the interaction between the main
pmchart window and the samples settings dialog - the values
are reset incorrectly to the default values each time the
dialog is popped up, and sometimes the dialog does not popup
at all as a result of delayed dialog creation.  This commit
fixes both of these problems.

This resolves Fedora bug #968825.

tjanez/pcp,tjanez/pcp,wuliming/pcp,adfernandes/pcp,adfernandes/pcp,edwardt/pcp,edwardt/pcp,prasincs/pcp,tjanez/pcp,wuliming/pcp,tjanez/pcp,edwardt/pcp,tjanez/pcp,mbaldessari/pcp,wuliming/pcp,prasincs/pcp,edwardt/pcp,prasincs/pcp,andyvand/cygpcpfans,aeg-aeg/pcpfans,adfernandes/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,andyvand/cygpcpfans,edwardt/pcp,adfernandes/pcp,aeg-aeg/pcpfans,prasincs/pcp,prasincs/pcp,aeg-aeg/pcpfans,tjanez/pcp,prasincs/pcp,andyvand/cygpcpfans,tjanez/pcp,wuliming/pcp,aeg-aeg/pcpfans,adfernandes/pcp,aeg-aeg/pcpfans,edwardt/pcp,aeg-aeg/pcpfans,wuliming/pcp,mbaldessari/pcp,edwardt/pcp,tjanez/pcp,mbaldessari/pcp,andyvand/cygpcpfans,adfernandes/pcp,edwardt/pcp,prasincs/pcp,andyvand/cygpcpfans,wuliming/pcp,aeg-aeg/pcpfans,prasincs/pcp,andyvand/cygpcpfans,adfernandes/pcp,wuliming/pcp,adfernandes/pcp,wuliming/pcp,mbaldessari/pcp,andyvand/cygpcpfans,mbaldessari/pcp,andyvand/cygpcpfans