Stop throwing error if repo update check failed

[taylortom]

Fixes #1763

[tomgreenfield]

Script is erroring:

$ node install
D:\adapt_authoring\lib\installHelpers.js:220
      logger.warn(`Couldn't check latest version of ${repoName}\n${error}`);
      ^

ReferenceError: logger is not defined
    at Request._requestHandler [as _callback] (D:\adapt_authoring\lib\installHelpers.js:220:7)
    at self.callback (D:\adapt_authoring\node_modules\request\request.js:186:22)
    at emitOne (events.js:96:13)
    at Request.emit (events.js:188:7)
    at Request.onRequestError (D:\adapt_authoring\node_modules\request\request.js:878:8)
    at emitOne (events.js:96:13)
    at ClientRequest.emit (events.js:188:7)
    at TLSSocket.socketErrorListener (_http_client.js:310:9)
    at emitOne (events.js:96:13)
    at TLSSocket.emit (events.js:188:7)
    at connectErrorNT (net.js:1025:8)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickDomainCallback (internal/process/next_tick.js:128:9)

[dancgray]

@taylortom This is still falling over with no internet. Is that expected?

[taylortom]

Apologies @dancgray, have amended a broken if