Log Message:
shells/elvish: update to 0.19.2

The tagging of 0.19.1 was also not done correctly - the code would still
advertise it as 0.19.0 when built. To fix this I tagged 0.19.2 with the correct
version information.

0.19.[012] all have the same functionalities, and packagers are advised to
package 0.19.2 only. Sorry for the confusion.