rpcclient: add timeout to http request.

[ziggie1984]

Not sure why we did not have a timeout in the first place, but I think it makes sense. Did not choose to add it as a config value but can be changed.

[coveralls]

Pull Request Test Coverage Report for Build 11269939212

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 45 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.08%) to 57.149%

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Files with Coverage Reduction	New Missed Lines	%
peer/peer.go	9	73.49%
wire/msgaddrv2.go	16	51.72%
wire/netaddressv2.go	20	74.45%

Totals
Change from base Build 11236152006:	-0.08%
Covered Lines:	29816
Relevant Lines:	52172

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💛 - Coveralls

[yyforyongyu]

I think this is usually 60s in "traditional" business...