If Davis wanted war he would of consented to Beauregard's whishes to take D.C. right after Bull Run. At best, or worst, Sumter was a misunderstanding that Linclon took advantage of. I know all of that damaged union granite was held sacred in the North, or so the propaganda said.
In the first place the war had already been underway for three months by the time of Bull Run. In the second place, Beauregard and his army were incapable of taking D.C. right after Bull Run.
Any misunderstanding was on the part of Davis when he thought that the south could win the war against the Union. He badly overestimated his own and the south's abilities and underestimated Lincoln's and the North's resolve.