kactivitymanagerd: add boost to DEPENDS

| -- The following REQUIRED packages have not been found:
|
|  * Boost (required version >= 1.49)
|
| CMake Error at /home/superandy/tmp/oe-core-glibc/sysroots/x86_64-linux/usr/share/cmake-3.6/Modules/FeatureSummary.cmake:556 (message):
|   feature_summary() Error: REQUIRED package(s) are missing, aborting CMake
|   run.

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>

recipes-kde/plasma/tier3/kactivitymanagerd/kactivitymanagerd.bb

@@ -8,6 +8,7 @@ LIC_FILES_CHKSUM = " \
 inherit kde-plasma
 
 DEPENDS += " \
+    boost \
     kdbusaddons \
     ki18n \
     kcoreaddons \