Bugfix: Lbank infinite loop

[gloriousCode]

Fixes an infinite loop when running GetOrderHistory on LBank. Discovered when testing #353

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

#353
GetOrderHistory finishes executing.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation and regenerated documentation via the documentation tool
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally and on Travis with my changes
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

Merging #355 into master will decrease coverage by 0.39%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master     #355     +/-   ##
=========================================
- Coverage   43.91%   43.52%   -0.4%     
=========================================
  Files         129      129             
  Lines       31011    31009      -2     
=========================================
- Hits        13620    13498    -122     
- Misses      16335    16394     +59     
- Partials     1056     1117     +61

Impacted Files	Coverage Δ
exchanges/lbank/lbank_wrapper.go	7.32% <0%> (+0.04%)	⬆️
exchanges/gemini/gemini.go	80% <0%> (-5.08%)	⬇️
exchanges/poloniex/poloniex_wrapper.go	33.47% <0%> (-4.14%)	⬇️
exchanges/anx/anx.go	64.35% <0%> (-3.79%)	⬇️
exchanges/binance/binance.go	78.55% <0%> (-3.51%)	⬇️
exchanges/localbitcoins/localbitcoins.go	52.53% <0%> (-3.21%)	⬇️
exchanges/binance/binance_wrapper.go	43.3% <0%> (-3.15%)	⬇️
exchanges/bitstamp/bitstamp_wrapper.go	31% <0%> (-3.11%)	⬇️
exchanges/anx/anx_wrapper.go	31.43% <0%> (-3.04%)	⬇️
exchanges/localbitcoins/localbitcoins_wrapper.go	35.31% <0%> (-2.98%)	⬇️
... and 3 more

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[shazbert]

utACK

[thrasher-]

utACK due to no orders on exchange, but the logic looks good. Nice find!