micro-osd.sh: Clarify the suspicion around S3 credentials

It's unusual to put any kind of credentials out in open. The set
of credentials defined with `S3_ACCESS_KEY` and `S3_SECRET_KEY`
variables in the script are questionable in its nature. But these
are not real/valid credential values in any form for AWS rather
used for testing the S3 compatible API from Ceph RGW. Therefore
clarify the intention and replace with sample values from official
AWS documentation.

Signed-off-by: Anoop C S <anoopcs@cryptolab.net>

Author: anoopcs9

micro-osd.sh

@@ -39,10 +39,15 @@ MON_NAME="a"
 MGR_NAME="x"
 MIRROR_ID="m"
 RGW_ID="r"
-S3_ACCESS_KEY=2262XNX11FZRR44XWIRD
-S3_SECRET_KEY=rmtuS1Uj1bIC08QFYGW18GfSHAbkPqdsuYynNudw
-HOST_IP=$(getent ahostsv4 "${HOSTNAME}" | grep STREAM | head -n 1 | awk '{print $1}')
 
+# Following are examples for S3 credentials taken from official AWS docs:
+# https://docs.aws.amazon.com/IAM/latest/UserGuide/security-creds.html#access-keys-and-secret-access-keys
+# These does not represent real/valid credentials for AWS in any form.
+# They are exclusively used for testing S3 compatible API from Ceph RGW.
+S3_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+S3_SECRET_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+
+HOST_IP=$(getent ahostsv4 "${HOSTNAME}" | grep STREAM | head -n 1 | awk '{print $1}')
 FSID="$(uuidgen)"
 export CEPH_CONF=${DIR}/ceph.conf