telepathy: add dbus-glib-1 to link flags

[larchunix]

Fix compilation with -Wl,z,defs / -Wl,--no-undefined in CFLAGS.

Resolves #1432.

[antenore]

Thanks @larchunix I'll merge this as soon as travis will build it.

[antenore]

The travis build failed because I've triggered a new one by hand. I've had to add a parameter in travis to wait at least 20 minutes during both the install and deploy phases.

https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received

I'm merging this PR. Thanks a lot @larchunix !!!!!!!!!!!!!!!!!!!!!!!!!!!

@giox069 FYI