network: Use local variables in networkUpdatePortBandwidth

network: Use local variables in networkUpdatePortBandwidth

We go through the trouble of checking {old|new}Bandwidth[->in] and
storing the result in local @old_floor and @new_floor, but then
we don't use them. Instead we make derefs to the longer name. This
caused Coverity to note dereferencing newBandwidth->in without first
checking @newBandwidth like was done for new_floor could cause a
NULL dereference.

Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>