Pepare for v1.2 release.

Reviewed in https://codereview.appspot.com/10841043/.
diff --git a/apiclient/__init__.py b/apiclient/__init__.py
index 6a74889..fe31691 100644
--- a/apiclient/__init__.py
+++ b/apiclient/__init__.py
@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "1.1"
+__version__ = "1.2"