Remove comment about 1024/1023 RSA key lengths that's no longer true as of

r9421.

[originally from svn r9422]
[r9421 == 9604c2b367]

doc/pubkey.but

@@ -151,18 +151,6 @@ of the key PuTTYgen will generate.
 
 Currently 1024 bits should be sufficient for most purposes.
 
-Note that an RSA key is generated by finding two primes of half the
-length requested, and then multiplying them together. For example,
-if you ask PuTTYgen for a 1024-bit RSA key, it will create two
-512-bit primes and multiply them. The result of this multiplication
-might be 1024 bits long, or it might be only 1023; so you may not
-get the exact length of key you asked for. This is perfectly normal,
-and you do not need to worry. The lengths should only ever differ by
-one, and there is no perceptible drop in security as a result.
-
-DSA keys are not created by multiplying primes together, so they
-should always be exactly the length you asked for.
-
 \S{puttygen-generate} The \q{Generate} button
 
 \cfg{winhelp-topic}{puttygen.generate}