Fix "function not found" failure

POSIX compliant shell does not recognize keyword
"function" and run the script under bash.

Issue-ID: AAF-430
Change-Id: I608070f41462cc5a1cba3cd112483a19fad38615
Signed-off-by: Manjunath Ranganathaiah <manjunath.ranganathaiah@intel.com>
diff --git a/jjb/aaf/build-sshsm-docker-images.sh b/jjb/aaf/build-sshsm-docker-images.sh
index b70c13d..7ed0719 100755
--- a/jjb/aaf/build-sshsm-docker-images.sh
+++ b/jjb/aaf/build-sshsm-docker-images.sh
@@ -8,4 +8,4 @@
 echo 'Building AAF/sshsm base containers'
 cd bin/base
 chmod 755 build_base_images.sh
-sh build_base_images.sh
+./build_base_images.sh