KNOX-3024 - Fixed Java finding issues

[smolnar82]

What changes were proposed in this pull request?

I updated the existing login in knox-functions.sh to successfully check Java executables under /usr if no JAVA_HOME is set or Java is not available on the path.
In addition to fixing the issue, I added an option to display the Java with the --verbose option (when using KnoxCLI, --verbose true should be used.

How was this patch tested?

Checked the updated scripts on shellcheck.net and tested them manually:

• gateway.sh

$ bin/gateway.sh restart --verbose
Found Java at /usr/local/opt/openjdk@8/bin/java
Stopping Gateway with PID 12173 succeeded.
Starting Gateway succeeded with PID 12346.

$ bin/gateway.sh restart
Stopping Gateway with PID 12346 succeeded.
Starting Gateway succeeded with PID 12419.

• knoxcli.sh

$ bin/knoxcli.sh export-cert --type JKS --verbose true
Found Java at /usr/local/opt/openjdk@8/bin/java
Certificate gateway-identity has been successfully exported to: /Users/sandormolnar/test/knoxGateway/data/security/keystores/gateway-client-trust.jks

$ bin/knoxcli.sh export-cert --type JKS
Certificate gateway-identity has been successfully exported to: /Users/sandormolnar/test/knoxGateway/data/security/keystores/gateway-client-trust.jks

• ldap.sh

$ bin/ldap.sh start --verbose
Found Java at /usr/local/opt/openjdk@8/bin/java
Starting LDAP succeeded with PID 12531.

$ bin/ldap.sh stop
Stopping LDAP with PID 12531 succeeded.

$ bin/ldap.sh start
Starting LDAP succeeded with PID 12573.

[moresandeep]

Looks good!

[moresandeep]

nitpick: May be accommodate shortform as well -v

[smolnar82]

KnoxCLI only supports --verbose, hence the long version only. Maybe later...

[moresandeep]

i see makes sense :)