Add qualifier default to alpha1 in build.gradle (#151)

Signed-off-by: Peter Zhu <[email protected]>

Author: peterzhuamazon

build.gradle

@@ -7,6 +7,8 @@ buildscript {
     ext {
         opensearch_group = "org.opensearch"
         opensearch_version = System.getProperty("opensearch.version", "2.0.0-alpha1-SNAPSHOT")
+        isSnapshot = "true" == System.getProperty("build.snapshot", "true")
+        buildVersionQualifier = System.getProperty("build.version_qualifier", "alpha1")
         kotlin_version = System.getProperty("kotlin.version", "1.6.10")
     }
 
@@ -38,11 +40,6 @@ repositories {
     maven { url "https://aws.oss.sonatype.org/content/repositories/snapshots" }
 }
 
-ext {
-    isSnapshot = "true" == System.getProperty("build.snapshot", "true")
-    buildVersionQualifier = System.getProperty("build.version_qualifier")
-}
-
 allprojects {
     group 'org.opensearch.commons'
     version = opensearch_version.tokenize('-')[0] + '.0'