Add abrt-java-connector bits

Honor JAVACMD_OPTS with a path to the abrt connector agent when:
  1. JAVA_ABRT environment variable does not hold 'off'
  2. the connector's library exists
  3. abrtd is running

We have to use JAVACMD_OTPS variable instead of FLAGS and OPTIONS
because applications (i.e. ant) migth use the following workflow:
  . /usr/share/java-utils/java-functions
  set_javacmd
  $JAVACMD MyClass

FLAGS and OPTIONS variables are used only from run() function.