adb: skip listenToSocket if openSocketLocked fails

listenToSocket used to be called even if
openSocketLocked fails which threw an NPE
because mInputStream was null.

Bug: 418795159
Test: v2/al-eng/al_dts_hw_postsubmit
Flag: EXEMPT bugfix
Change-Id: Ib73a094a529ba59ea028234b77328a6ef501fd9f
Signed-off-by: Roman Kiryanov <rkir@google.com>