[SPARK-2030] Bump SparkBuild.scala version number of branch-1.0 to 1.0.1-SNAPSHOT.

Author: Takuya UESHIN <ueshin@happy-camper.st>

Closes #975 from ueshin/issues/SPARK-2030 and squashes the following commits:

aae1044 [Takuya UESHIN] Bump version number to 1.0.1-SNAPSHOT.