Tests: Print p4.log on server failure in CTest.UpdateP4

Tests/CTestUpdateP4.cmake.in

@@ -66,6 +66,7 @@ for i in 1 2 3 4 5 6 7 8 9 10; do
   fi
 done
 echo 'Gave up waiting for server to start.'
+sed 's/^/  /' '${P4_ROOT}/p4.log'
 "
     )
 endif()
@@ -258,4 +259,4 @@ message("Shutting down p4d")
 run_child(
     WORKING_DIRECTORY ${TOP}
     COMMAND ${P4CMD} admin stop
-)
+)