Adopting new logic for the sensor ipmi plugin's configure.m4

With the current change the IPMI plugin will be:

    1. Disabled if explicitly stated by a 'with_ipmi_sensor=no'
    2. Enabled if explicitly stated by a 'with_ipmi=yes' and the
dependent ipmiutil libs are available.
    3. Enabled if 'with_ipmi_sensor' is not mentioned but the
dependent libraries are available

The ipmiutil libraries can be:
    1. Enabled 'with_ipmiutil=yes' or 'with_ipmiutil=/path/to/libs'
    2. Disabled 'with_ipmiutil=no' will disable the ipmiutil libs
    3. If 'with_ipmiutil' is not mentioned then it will be checked
depending on whether any other component using the ipmiutil libs
is enabled or disabled
Fixing code review comments for configure macros of IPMI sensor & IPMIUTIL
Addressing more review comments.
Merge branch 'vin_configure_fix'