[PATCH resend] webservices: Use sscanf to convert strings to doubles.

[Erich E. Hoover]

This removes the last "long double" instance impacted by commit
0e183cc3c0d3b6f89f79047cdd71c389afc75073.  Thanks go again to Piotr
for his help.

Next time I'll remember to wait for the VMs to update ;)

Best,
Erich