synchronize photo storage creation for race conditions.

Several exceptions were reported regarding "Unable to create photo storage
directory /data/user/0/com.android.providers.contacts/files/photos".
It might caused by the fact that File.makeDirs() is not thread safe.
So make it syncrhonized to resolve this issue.

Bug:17505392
Bug:17449819
Change-Id: I494204424c024c2166340af609423a669e741761
1 file changed