Make dumpRSAPublicKey also accept a public key in PEM format

Make dumpRSAPublicKey also accept a public key in PEM format

This change makes dumpRSAPublicKey directly accept a public key in PEM format. This makes it possible to avoid the unnecessary step of generating a self-signed certificate to dump the public key in .keyb format.

The old style certificate input is still accepted.

Using certs (as done previously):
dumpRSAPublicKey -cert <certfile> 

Directly using public keys:
dumpRSAPublicKey -pub <pubfile>

Change-Id: Ic35b59aff6613d145d7947212650da281f734b74

BUG=7576
TEST=manual

$ openssl genrsa -F4 -out test.pem 4096
$ openssl rsa -in test.pem -out test.pub
$ dumpRSAPublicKey -pub test.pub >test.pub.keyb

Verify that this matches the output we get using the old style <cert> input.

$ openssl req -batch -new -x509 -key test.pem -out test.cert
$ dumpRSAPublicKey -cert test.cert >test.cert.keyb
$ diff test.pub.keyb test.cert.keyb
$

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=551037b

[Randall Spangler, 2010-11-01 15:54:49]

LGTM