Unwarn on clang

qdeclarativebluetoothservice.cpp:279:14: warning: variable 'serverType'
is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]

Change-Id: I67e6e58c7729d09492a7913e83b4bc94acf5d057
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>