Fix tool-messages target
Fix tool-messages target

Make tool-messages should create a mkTools.po file with all messages which
can be generated by any of the mkTools.

Correct the macro name which gettext searches for to LE_I18N.

Resolves: LE-6542
Change-Id: If3287710afaa8551b5759a3162ea0c8770f13d55

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af