When linking with ICU4C, -licudata should be included in command line on Linux

When using icu4c built as archives, link lines need to include the data library to resolve all symbol references. The two cases so far are in icu/icu.pro and tools/tools.pri:

qt-everywhere-opensource-src-5.2.1/qtbase/config.tests/unix/icu/icu.pro: LIBS += -licui18n -licuuc -licudata

qt-everywhere-opensource-src-5.2.1/qtbase/src/corelib/tools/tools.pri: LIBS_PRIVATE += -licui18n -licuuc -licudata

With shared libraries, library dependencies will solve the resolution problem. Archives need this to be explicit to pick up the data. It may be that other ICU build/package styles will have problems with this so it may need to be looked at more carefully.