pginstaller - pginst: Change PostGIS install to use template_postgis,

Log Message:
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Change PostGIS install to use template_postgis, per their new standard.

C patch from Mark Cave-Ayland. C-hackery and wxs adjustments by me.

Modified Files:
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pginst/ca:
pginstca.c (r1.101 -> r1.102)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pginstaller/pginst/ca/pginstca.c.diff?r1=1.101&r2=1.102)
pginst/wxs:
dialogs.wxs (r1.57 -> r1.58)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pginstaller/pginst/wxs/dialogs.wxs.diff?r1=1.57&r2=1.58)
pginst.wxs (r1.177 -> r1.178)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pginstaller/pginst/wxs/pginst.wxs.diff?r1=1.177&r2=1.178)