Unable to fully catch exception when IQ# is not installed

[pedrorrivero]

Due to the message that gets printed if IQ# is not installed, we cannot provide seamless functionality around qsharp catching the exception (i.e. we always get an error message displayed even with try-except logic).

iqsharp/src/Python/qsharp-core/qsharp/clients/__init__.py

Lines 42 to 44 in 0b78bc4

	message = "IQ# is not installed." + \
	"\nPlease follow the instructions at https://aka.ms/qdk-install/python."
	print(message)

The line above should simply be included in the raised error message instead of printed out.