Cherry-pick bug fixes from master.
Cherry-pick bug fixes from master.

1. Set correct aidl_preprocess_import for LOCAL_SDK_VERSION current.
2. Set correct PRIVATE_BOOTCLASSPATH for non-empty LOCAL_SDK_VERSION.

Change-Id: Iff8e266931434863521bfa4621767bed31d31cc0

hagar006/platform_manifest,fallouttester/platform_manifest,xorware/android_build,RR-msm7x30/platform_manifest,see4ri/lolili,ND-3500/platform_manifest,knone1/platform_manifest,xorware/android_build,xorware/android_build,xorware/android_build,Hybrid-Power/startsync,pranav01/platform_manifest,xorware/android_build