Revert "increase default disk size"

This reverts commit ccc5c502.

openappstack/cluster.py

@@ -32,7 +32,7 @@ log = logging.getLogger(__name__)  # pylint: disable=invalid-name
 """Greenhost region where VPS will be started with create_droplet"""
 DEFAULT_REGION = 'ams1'
 """Default disk size"""
-DEFAULT_DISK_SIZE_GB = 35
+DEFAULT_DISK_SIZE_GB = 30
 """Default amount of memory"""
 DEFAULT_MEMORY_SIZE_MB = 12288
 """Default "image" (operating system): 26  =  Debian bullseye-x64 """