Change the .text-too-small error message.

The original error message apparently doesn't mean anything to users, and this can be easily improved.  See the following:
https://community.rapid7.com/thread/2356

The updated will display an error like this:

	[*] x86/shikata_ga_nai succeeded with size 53308 (iteration=1)

	[*] x86/shikata_ga_nai succeeded with size 53337 (iteration=2)

	[*] x86/shikata_ga_nai succeeded with size 53366 (iteration=3)

	[*] x86/shikata_ga_nai succeeded with size 53395 (iteration=4)

	[*] x86/shikata_ga_nai succeeded with size 53424 (iteration=5)

	[-] x86/shikata_ga_nai failed: The .text section is too small. Minimum is 54908 bytes, your .text size is 45056 bytes
	[-] No encoders succeeded.

And then at that point, they will know why it's not working for them.