Valgrind: Avoid passing empty argument

Change-Id: Id0915718cb6b76c227ded0f418bf3c5aadcb9f35
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/valgrind/valgrindprocess.cpp

@@ -310,7 +310,8 @@ void ValgrindProcess::findPIDOutputReceived()
 QString ValgrindProcess::argumentString(Utils::OsType osType) const
 {
     QString arguments = Utils::QtcProcess::joinArgs(m_valgrindArguments, osType);
-    Utils::QtcProcess::addArg(&arguments, m_debuggeeExecutable, osType);
+    if (!m_debuggeeExecutable.isEmpty())
+        Utils::QtcProcess::addArg(&arguments, m_debuggeeExecutable, osType);
     Utils::QtcProcess::addArgs(&arguments, m_debuggeeArguments);
     return arguments;
 }