Change currency mnemonic for "New Israeli Shekel" from "ILS" to "NIS".

[Christian Stimming]

Log Message:
-----------
Change currency mnemonic for "New Israeli Shekel" from "ILS" to
	"NIS". Fixes #152755.

Tags:
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gnucash-1-8-branch

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/engine:
        gnc-commodity.c
        iso-4217-currencies.scm