blast.rb: improved error scraping from BLAST+'s stderr
blast.rb: improved error scraping from BLAST+'s stderr

Covers more type of errors in less lines of code.

Signed-off-by: Anurag Priyam <6e6ab5ea9cb59fe7c35d2a1fc74443577eb60635@gmail.com>

elsiklab/sequenceserver,elsiklab/sequenceserver,yeban/sequenceserver,IsmailM/sequenceserver,jasminZ/sequenceserver,aldermossy/sequenceserver,deepakunni3/sequenceserver,elsiklab/sequenceserver,deepakunni3/sequenceserver,vivekiitkgp/sequenceserver,IsmailM/sequenceserver,yeban/sequenceserver,lepbase/lepbase-sequenceserver,lepbase/lepbase-sequenceserver,yeban/sequenceserver,jasminZ/sequenceserver,aldermossy/sequenceserver,yeban/sequenceserver,deepakunni3/sequenceserver,aldermossy/sequenceserver,aldermossy/sequenceserver,lepbase/lepbase-sequenceserver,jasminZ/sequenceserver,vivekiitkgp/sequenceserver,IsmailM/sequenceserver,vivekiitkgp/sequenceserver