It`s just licks from the E-minor Blues scale. The scale looks like this.
E A D G B E
[12] [12] [12] [12] [12] [12]
[13]
[14] [14] [14]
[15] [15] [15] [15]
It`s jsut some licks form that, you can make them up, it still sounds good, but the solo is done in that scale.