Fix conflict if paramName is data

[lingster]

If a the paramName inside a swagger doc is called data then the generated code does not compile.

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[wing328]

Shippable issue already resolved in the master

[wing328]

@lingster thanks for the PR. We can go with your fix but later I may file a PR to add localVar as a prefix to all local variables.

[lingster]

@wing328 thabks for merging, PR for localvar for all local variables makes sense

[wing328]

@lingster thanks for the PR, which has been included in v4.2.0 release: https://twitter.com/oas_generator/status/1189824932345069569