Clarify comment about TLS versions

The previous comment used "TLS" as a shortcut for "TLS 1.0/1.1" which was
confusing. This partially reflected the names of the calc_verify/finished that
go ssl, tls (for 1.0/1.1) tls_shaxxx (for 1.2), but still it's clearer to be
explicit in the comment - and perhaps in the long term the function names
could be clarified instead.

library/ssl_tls.c

@@ -1528,7 +1528,7 @@ end:
 }
 
 /*
- * Set appropriate PRF function and other SSL / TLS / TLS1.2 functions
+ * Set appropriate PRF function and other SSL / TLS 1.0/1.1 / TLS1.2 functions
  *
  * Inputs:
  * - SSL/TLS minor version