Fix enable profiling's if condition.
Fix enable profiling's if condition.

Without this calling enable profiling twice leaves both the profiling
and non-profiling jar in ${distrodir}, which creates problems after
profiling is disabled.

iafek/kiji-base,iafek/kiji-base,rpinzon/kiji-schema,rpinzon/kiji-schema,kijiproject/kiji-schema,kijiproject/kiji-schema