Issue #112 using a DSA key results in an rPM package with an unverifi…

[bschelberg]

Using a DSA key results in an RPM package with an unverifiable signature

It seems like DSA has been deprecated by some projects, and we're strongly
encouraged to move to RSA. However, Redline RPM currently accepts DSA
keys for sigining, but signs the package incorrectly, resulting in
errors from RPM with errors that are difficult to diagnose.

[kkolinko]

I do not like this.

1. It breaks the feature implemented by Make RPM task not fail when the signature cannot be read #77
   In scenario of Make RPM task not fail when the signature cannot be read #77 your getAlgorithm() call will return null and you will fail with IAE.
   Expected behaviour is to fall through and set this.enabled=false,

2. It does not solve the issue of wrong signature by generating a correct one. It just disallows one to generate any other signature besides RSA.