We've had a good number of reports of schannel errors. We should parse these errors and present a more helpful dialog.

• Unable to check revocation for the certificate #3300
• git clone fail. SSL Proxy error.  #3316
• Error "Unknown error (0x80092013)" on push/pull to Enterprise instance #3260
• Unable to sync repositories using GitHub Desktop: fatal error 0x80092012 #3156
• Unable to clone, fetch, or push on GitHub (with enterprise TLS/SSL Inspection) #2920
• schannel: next InitializeSecurityContext failed: Unknown error (0x80092012) - The revocation function was unable to check revocation for the certificate #2884
• The revocation function is unable to check revocation for the certificate. #2471
• SSL error when publishing repo #2452
• Clone failed: The revocation function was unable to check revocation because the revocation server was offline. #2414
• [Error] InitializeSecurityContext failed: Unknown error (0x80092013)  #2187