Don't suggest writing to /tmp if we already are

Small fix to not write the suggestion line about saving to
/data/local/tmp/ if that's what we're already trying to do but the
actual problem is file permissions (eg from adb unroot)

Test: adb shell am dumpheap com.android.systemui /data/local/tmp/systemui.hprof
Test: adb shell am dumpheap com.android.systemui /tmp/systemui.hprof
Change-Id: I201456a4a72e3d5c988a14590374b2dd559b97d2