SQUISH: Use env var for src path if available.

Change-Id: I1844db3bb3dc5eca0c434089288916ac86db775a
Reviewed-by: Christian Stenger <christian.stenger@nokia.com>

tests/system/shared/qtcreator.py

@@ -63,7 +63,7 @@ else:
     cwd = os.getcwd()       # current dir is directory holding qtcreator.py
     cwd+="/../../settings/unix"
     defaultQtVersion = "Desktop Qt 4.7.4 for GCC (Qt SDK)"
-srcPath = sdkPath + "/src"
+srcPath = os.getenv("SYSTEST_SRCPATH", sdkPath + "/src")
 
 cwd = os.path.abspath(cwd)
 tmpSettingsDir = tempDir()