Fix some warnings found by QNX's compiler

-Werror is now disabled for that compiler, but it doesn't hurt to fix.

io/qstandardpaths_unix.cpp:149:32: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
qtestcase.cpp:2330:31: error: narrowing conversion of '(ms / 1000)' from 'int' to '_Timet {aka unsigned int}' inside { } [-Werror=narrowing]

Change-Id: Id92f4a61915b49ddaee6fffd14aea2c1e686e8f2
Reviewed-by: Samuli Piippo <samuli.piippo@qt.io>

src/corelib/io/qstandardpaths_unix.cpp

@@ -117,7 +117,7 @@ QString QStandardPaths::writableLocation(StandardLocation type)
     }
     case RuntimeLocation:
     {
-        const uid_t myUid = geteuid();
+        const uint myUid = uint(geteuid());
         // http://standards.freedesktop.org/basedir-spec/latest/
         QFileInfo fileInfo;
         QString xdgRuntimeDir = QFile::decodeName(qgetenv("XDG_RUNTIME_DIR"));

src/testlib/qtestcase.cpp

@@ -2246,7 +2246,7 @@ void QTest::qSleep(int ms)
 #elif defined(Q_OS_WIN)
     Sleep(uint(ms));
 #else
-    struct timespec ts = { ms / 1000, (ms % 1000) * 1000 * 1000 };
+    struct timespec ts = { time_t(ms / 1000), (ms % 1000) * 1000 * 1000 };
     nanosleep(&ts, NULL);
 #endif
 }