In the specification of lint is the Serverity of information given as
the String "Information"
(http://grepcode.com/file/repo1.maven.org/maven2/com.android.tools.lint/lint_api/r16/com/android/tools/lint/detector/api/Severity.java).
Further more here is an result-example:
<issue id="OldTargetApi" severity="Information" message="Not
targetin..........">

In the file: android-lint-plugin / src / main / java / org / jenkinsci
/ plugins / android_lint / parser / LintParser.java

in your method:

private Priority getPriority(String severity) {
if (SEVERITY_FATAL.equals(severity) ||
SEVERITY_ERROR.equals(severity))

{ return Priority.HIGH; }

if (SEVERITY_INFORMATIONAL.equals(severity))

{ return Priority.LOW; }

return Priority.NORMAL;
}

you check against the constant SEVERITY_INFORMATIONAL which is
"Informational", this is wrong. As you can see in the specification
the string itself should be "Information".

The correct constant should be:
/** Severity constant value from

{@link com.android.tools.lint.detector.api.Severity}

. */
private static final String SEVERITY_INFORMATIONAL = "Information";