[SPARK-2029] Bump pom.xml version number of master branch to 1.1.0-SNAPSHOT.

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

Closes #974 from ueshin/issues/SPARK-2029 and squashes the following commits:

e19e8f4 [Takuya UESHIN] Bump version number to 1.1.0-SNAPSHOT.